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    Wyświetlanie 1-85 z 85
    Tytuł:
    Komputerowe wspomaganie projektowania zmechanizowanych obudów ścianowych według metody Zakładu Remontowo-Produkcyjnego KW S.A.
    Computer aided design of powered roof supports according to method of Zakład Remontowo-Produkcyjny KW S.A.
    Autorzy:
    Karczewski, T.
    Czarnota, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/113740.pdf
    Data publikacji:
    2016
    Wydawca:
    STE GROUP
    Tematy:
    obudowa zmechanizowana
    optymalizacja
    proces projektowania
    układ lemniskatowy
    powered roof support
    optimization
    design process
    lemniscate mechanism
    Opis:
    Prezentacja autorskiego programu obliczeniowego Zakładu Remontowo-Produkcyjnego, którego zadaniem jest usprawnienie procesu projektowania obudowy zmechanizowanej.
    Presentation of Zakład Remontowo-Produkcyjny’s copyright calculation program, tasked with improving of the design of powered roof support.
    Źródło:
    Systemy Wspomagania w Inżynierii Produkcji; 2016, 1 (13); 407-417
    2391-9361
    Pojawia się w:
    Systemy Wspomagania w Inżynierii Produkcji
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Doping and Characterization of Wide-Gap II-VI Epilayers
    Autorzy:
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1946648.pdf
    Data publikacji:
    1996-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.55.Ln
    71.55.-i
    71.55.Gs
    Opis:
    In this paper we review the properties of n-type doped ZnSe and CdTe epilayers grown by molecular beam epitaxy on (100) GaAs substrates. Recent results of photoluminescence, transport measurements, secondary ion mass spectroscopy and deep-level transient spectroscopy are discussed. A major emphasis is placed on the effect of different dopant species and the role of the deviation from stoichiometry on the doped epitaxial layers. Since deep defect states play an important role in determining the properties of the doped materials, considerable attention is directed towards characterization and identification of deep-lying defect states, both native and introduced by dopants. In particular, in the case of ZnSe the deep-level transient spectroscopy results clarify why Cl is superior to Ga as an effective n-type dopant. They provide strong evidence that chlorine - unlike Ga - does not introduce by itself any detectable deep defects into the ZnSe lattice. In the case of CdTe, we focus on the influence of the deviation from stoichiometric growth conditions in the molecular beam epitaxy process and on the properties of In doped layers. We discuss resistivity, Mn diffusivity and the presence of various deep defects in layers grown at different Cd/Te flux ratios.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 4; 635-644
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Operational malfunctions of turbochargers – reasons and consequences
    Niesprawności eksploatacyjne turbosprężarek, ich przyczyny i skutki
    Autorzy:
    Dziubak, T.
    Karczewski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/134174.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Naukowe Silników Spalinowych
    Tematy:
    combustion engine
    intake system
    turbocharger
    operational malfunctions
    silnik spalinowy
    układ dolotowy
    turbosprężarka
    niesprawności eksploatacyjne
    Opis:
    The paper discusses the most frequently occurring types of damage in turbochargers fitted in modern combustion engines and their influence on the engine basic operational indexes. The following causes of turbocharger malfunctions have been discussed: no lubrication, low lubricant pressure, reduced lubricant quality, foreign objects in the charged air and in the exhaust gas. Example malfunctions resulting from the said causes have been shown. The experimental part discusses the influence of a reduction of the charging pressure resulting from a leakage in the intake system on the effective parameters of a diesel engine fitted in light-duty and heavy-duty vehicles. The leakage in the intake system has been simulated by boring holes of the diameter of 3 and 12 mm in the intake manifold downstream of the turbocharger. The influence has been determined of the leakage of the turbocharging system on the value of the charging pressure, maximum effective power, engine torque, unit and hourly fuel consumption and the concentration of the exhaust components. A significant impact has been observed of the leakage of the turbocharging system on the effective parameters of the tested diesel engine and exhaust gas composition.
    W artykule wskazano najczęściej występujące uszkodzenia turbosprężarek stosowanych we współczesnych silnikach spalinowych oraz przedstawiono ich wpływ na podstawowe wskaźniki operacyjne silników. Omówiono takie niesprawności turbosprężarek, jak: brak smarowania lub zbyt małe ciśnienie czynnika smarującego, jakość oleju smarującego, obecność ciał obcych w powietrzu i w spalinach. Przedstawiono przykładowe niesprawności spowodowane poszczególnymi czynnikami. W części doświadczalnej oceniono wpływ zmniejszenia ciśnienia doładowania spowodowanego nieszczelnością układu dolotowego na parametry użyteczne silnika o zapłonie samoczynnym, stosowanego w samochodach dostawczych oraz osobowych. Nieszczelność układu dolotowego została zamodelowana przez wykonanie otworów o średnicy 3 i 12 mm w kolektorze dolotowym za turbosprężarką. Określono wpływ nieszczelności układu doładowania na wartość ciśnienia doładowania, maksymalną moc użyteczną, moment obrotowy silnika, jednostkowe i godzinowe zużycie paliwa oraz stężenie składników toksycznych w spalinach. Stwierdzono istotny wpływ nieszczelności układu doładowania na parametry użyteczne i skład spalin silnika o zapłonie samoczynnym.
    Źródło:
    Combustion Engines; 2016, 55, 1; 13-21
    2300-9896
    2658-1442
    Pojawia się w:
    Combustion Engines
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kolorymetryczne oznaczanie cynku w wodzie z użyciem dwu-b-naftylotiokarbazonu (DBN)
    Colorimetric estimation of zinc in water with di-b-naphthylthiocarbazone (DBN)
    Autorzy:
    Karczewski, J.
    Januszko, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/871746.pdf
    Data publikacji:
    1977
    Wydawca:
    Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
    Tematy:
    wskazniki kolorymetryczne
    zawartosc cynku
    cynk
    woda
    dwu-b-naftylotiokarbazon
    odczynniki
    Źródło:
    Roczniki Państwowego Zakładu Higieny; 1977, 28, 1
    0035-7715
    Pojawia się w:
    Roczniki Państwowego Zakładu Higieny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ferroelectric Field Effect Transistor Based on Modulation Doped CdTe/CdMgTe Quantum Wells
    Autorzy:
    Kolkovsky, V.
    Wojciechowski, T.
    Wojtowicz, T.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811945.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    77.80.-e
    77.80.Fm
    85.50.Gk
    73.61.Ga
    Opis:
    In this work, we observed effects of changing the electron concentration and electron mobility upon the poling of the $Cd_{0.96}Zn_{0.04}Te$ ferroelectric gate deposited on the top of the CdTe-based modulation doped quantum well structure, which are confirmation of the existence of the electrostatic field originating from the ferroelectric material, which can be controlled by an external voltage. The analysis of the data obtained from the Hall effect measurements showed that the electron mobility and carrier concentration decreased by a factor of 2.5 and 1.5, respectively upon the negative poling of the gate with respect to the poled by the positive voltage. Moreover, the electrostatic field, depending on its directions, causes depletion of accumulation of electrons in the 2D channel, i.e., it is a source of the field effect.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1173-1178
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oznaczanie jodu w moczu z zastosowaniem metody ekstrakcji butanolem
    Opredelenie jjoda v moche s primeneniem metoda ehkstrakcii butanolom
    Iodine determination in urine using the method of butanol extraction
    Autorzy:
    Karczewski, J.
    Januszko, T.
    Suszczyńska-Falecka, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/2188622.pdf
    Data publikacji:
    1979
    Wydawca:
    Polskie Towarzystwo Diagnostyki Laboratoryjnej
    Źródło:
    Diagnostyka Laboratoryjna; 1979, 15, 5; 229-234
    0867-4043
    Pojawia się w:
    Diagnostyka Laboratoryjna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Search for Dimensional Effects in Spin-Glass Transition in Thin Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Multilayers
    Autorzy:
    Sawicki, M.
    Dietl, T.
    Skośkiewicz, T.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1943818.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.Rr
    75.50.Lk
    75.30.Kz
    75.50.-y
    Opis:
    SQUID magnetic measurements of CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te, x ≃ 0.5, multi-layers with different CdMnTe layer thickness w reveal the persistence of the spin-glass irreversibilities down to ≃ 16 Å thin layers, i.e., well beyond the previously postulated 40 Å as a quasi-2D threshold. The freezing temperature T$\text{}_{f}$ is found to be a monotonic function of w, and it obeys a scaling law T$\text{}_{f}$ ∝ w$\text{}^{a}$, with a 0.8 similar to that for canonical spin-glasses. Magnetic properties of all studied structures are found to be independent of the orientation of the magnetic field.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 1038-1042
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Graded Quantum Well Structures Made of Diluted Magnetic Semiconductors
    Autorzy:
    Wojtowicz, T.
    Kutrowski, M.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968998.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    78.55.Et
    Opis:
    In this paper we review results of studies of two types of spatially graded quantum well structures containing various layers of diluted magnetic semiconductors Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te or Cd$\text{}_{1-x-y}$Mn$\text{}_{x}$Mg$\text{}_{y}$Te. The design of the structures has been recently proposed by us and suitable samples have been grown by a modified molecular beam epitaxy method. In the structures of the first type a digital profiling of the composition of the constituent material in the growth direction allowed to produce quantum wells with a specifically required shape of the confining potential (including parabolic, half-parabolic, triangular, and trapezoidal). Such samples were used for (i) determination of the conduction and valence band offsets in MnTe/CdTe and MgTe/CdTe systems, (ii) for the demonstration of an enhanced exciton binding in a parabolic confining potential as well as for (iii) demonstration of the possibility of "spin-splitting engineering" in diluted magnetic semiconductors quantum structures. In the second type of the structures, a precise in-plane profiling of either quantum well width or the barrier width or n-type doping intensity was realized. These structures were subsequently used for studies of the evolution of optical spectra with an increase in the concentration of confined two-dimensional gas of conduction electrons.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 199-217
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stimulated and Laser Emission in CdZnTe/CdMnTe Double Quantum Well Heterostructures
    Autorzy:
    Kowalczyk, L.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933829.pdf
    Data publikacji:
    1995-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.45.+h
    71.55.Gs
    Opis:
    Stimulated emission by optical excitation has been investigated in CdZnTe/CdMnTe quantum well heterostructures. Laser action has been achieved at 4.2 K and at 77 K with relatively low threshold values of the excitation intensity. Photοluminescence excitation spectra of the stimulated emission were obtained indicating that the optical gain involves exciton-exciton inelastic scattering.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 4; 787-790
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Search for Dimensionality Crossover of Spin-Glass Freezing in Superlattices of Cd$\text{}_{0.50}$Mn$\text{}_{0.50}$Te/CdTe
    Autorzy:
    Sawicki, M.
    Dietl, T.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Skośkiewicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952078.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.-y
    75.50.Rr
    75.50.Lk
    Opis:
    SQUID measurements of the time decay of the thermoremanent magnetization (field-cooled in 1000 Oe) at long time scale, 10$\text{}^{2}$ < t < 10$\text{}^{5}$ s, are presented for MBE grown Cd$\text{}_{0.50}$Mn$\text{}_{0.50}$Te. We found that for both thin (32 Å) and thick (2500 Å) layers the spin-glass dynamics is characterized by a similar value of k = -(1/T$\text{}_{f}$)(dT$\text{}_{f}$/dlogt) > 0.05, indicating the absence of the phase transition at nonzero temperature under the experimental conditions.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 919-922
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Jod i wapń w wodach do picia woj. białostockiego
    Iodine and calcium in drinking water in the Białystok province
    Autorzy:
    Januszko, T.
    Karczewski, J.
    Poplawska, T.
    Smorczewska, B.
    Suszczynska-Falecka, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/873239.pdf
    Data publikacji:
    1977
    Wydawca:
    Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
    Tematy:
    woj.bialostockie
    woda pitna
    jod
    wapn
    zawartosc jodu
    zawartosc wapnia
    badania naukowe
    Źródło:
    Roczniki Państwowego Zakładu Higieny; 1977, 28, 5
    0035-7715
    Pojawia się w:
    Roczniki Państwowego Zakładu Higieny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electrical Properties of p-ZnTe/n-CdTe Photodiodes
    Autorzy:
    Chusnutdinow, S.
    Makhniy, V.
    Wojtowicz, T.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1409588.pdf
    Data publikacji:
    2012-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.15.Hi
    73.61.Ga
    85.60.Dw
    88.40.jm
    Opis:
    Current-voltage (I-V) and capacitance-voltage (C-V) characteristics of photovoltaic, thinfilm p-ZnTe/n-CdTe heterojunctions have been studied in the temperature range of 280-400 K. The p-n junctions were grown by MBE on (100) semi-insulating GaAs substrates. From the analysis of I-V and C-V curves the potential barrier height of the junctions and its temperature dependence are determined. The relatively large value of the temperature coefficient of the potential barrier height (2.5-3.0 × $10^{-3}$ eV/K) indicates a high density of defects at the p-ZnTe/n-CdTe interface. The presence of interface defects limits the efficiency of the solar energy conversion of these devices.
    Źródło:
    Acta Physica Polonica A; 2012, 122, 6; 1077-1079
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Changing the Properties of the CdTe/ZnTe Quantum Dots by in situ Annealing during the Growth
    Autorzy:
    Wojnar, P.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047681.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.De
    78.55.Et
    Opis:
    We present an attempt to control the properties of CdTe/ZnTe self-assembled quantum dots during their formation in the process of molecular beam epitaxy. Namely, the structures were in situ annealed at various temperatures and annealing times after the formation of quantum dots, before the deposition of a capping layer. Depending on the annealing parameters, the dots exhibit different optical properties which were studied by means of spatially resolved photoluminescence. From the analysis of these results, the information about relative changes of the average size and sheet density of quantum dots was extracted.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 283-288
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Częstośc występowania wola u dzieci zamieszkałych na wsi a stężenie jodu, wapnia i magnezu w wodach do picia na terenie woj. białostockiego
    Chastotnost' pojavlenija zoba u detejj prozhivajushhikh v derevne i koncentracija ioda kal'cija i magnija v pit'evojj vode na territorii belostokskogo voevodstva
    Goitre incidence in children living in villages in the Białystok region and the concentrations od iodine, calcium and magnesium in drinking water
    Autorzy:
    Januszko, T.
    Karczewski, J.
    Suszczynska-Falecka, Z.
    Rybaczuk, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/872482.pdf
    Data publikacji:
    1981
    Wydawca:
    Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
    Tematy:
    choroby czlowieka
    dzieci
    wole
    wies
    stezenie jodu
    stezenie wapnia
    stezenie magnezu
    woda
    Bialystok
    niedobor jodu
    zdrowie czlowieka
    Źródło:
    Roczniki Państwowego Zakładu Higieny; 1981, 32, 1
    0035-7715
    Pojawia się w:
    Roczniki Państwowego Zakładu Higieny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Epitaxial Growths of II-VI Compounds on (110) Substrates
    Autorzy:
    Cywiński, G.
    Wojtowicz, T.
    Kopalko, K.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969044.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.55.-a
    Opis:
    We studied epitaxial growth conditions of II-VI semiconductors on (110) substrates, which is indispensable for fabrication of T-shaped quantum wire structures. We experimented with different types of (110)-oriented substrates and monitored the surface quality of deposited layers in situ by reflection high energy electron diffraction and ex situ by photoluminescence. The aim of this work is to find optimum growth conditions of II-VI compounds on a cleaved edge of a superlattice as required by the overgrowth method.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 281-284
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    δ-Doped CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Multiple Quantum Wells Investigated by Photoreflectance Spectroscopy
    Autorzy:
    Sitarek, P.
    Misiewicz, J.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933972.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.72.Vv
    78.66.Hf
    Opis:
    Room temperature photoreflectance spectroscopy was used to investigate CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te multiple quantum wells grown by MBE. Structures were indium δ-doped into the well or into the barrier. The value of heavy and light hole subbands splitting was measured and compared to the calculated ones. The influence of the position of δ-doping on the measured spectra was shown.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 901-904
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Strain Relaxation of ZnTe/CdTe and CdTe/ZnTe heterostructures: In Situ Study
    Autorzy:
    Riesz, F.
    Kret, S.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952073.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.14.Hg
    68.55.Bd
    68.65.+g
    Opis:
    The strain relaxation kinetics of ZnTe/CdTe and CdTe/ZnTe heterostructures grown on GaAs substrates by molecular beam epitaxy are studied by in situ reflection high-energy electron diffraction. The observed critical layer thickness is 5 monolayers for ZnTe/CdTe and less than 1 monolayer for CdTe/ZnTe. The relaxation is anisotropic. Dislocation core parameters and relaxation rate constants were determined using a kinetic model and assuming strain-dependent activation energy of dislocation movement.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 911-914
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoluminescence of CdTe/CdMgTe Double Quantum Wells with a Two-Dimensional Electron Gas
    Autorzy:
    Deresz, M.
    Wiater, M.
    Karczewski, G.
    Wojtowicz, T.
    Łusakowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1033223.pdf
    Data publikacji:
    2017-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    CdTe/CdMgTe quantum wells
    magnetophotoluminescence
    Opis:
    Magnetophotoluminescence measurements at liquid helium temperatures were carried out on asymmetric double quantum wells based on CdTe/CdMgTe heterostructures. Due to doping with shallow iodine donors, a two-dimensional electron gas was present in the quantum wells. The samples studied differed with the quantum well widths and doping level. We show a resemblance of the luminescence to results obtained on single quantum wells which suggests that in samples studied the quantum wells are not strongly coupled.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 2; 390-392
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Search for T-Shaped Quantum Wires in CdTe/CdMg(Mn)Te System
    Autorzy:
    Cywiński, G.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Gębicki, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969038.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.15.Rn
    73.20.Dx
    85.40.Ux
    Opis:
    We attempted to produce and to investigate T-shaped wire structures of II-VI compounds. Our samples were grown on GaAs hybrid substrates in a two-stage growth process. The photoluminescence measurements resulted into two different possible polarization behaviors of recorder signal. We interpret one of these behaviors as due to quantum wire formation.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 277-280
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    High-Resolution X-Ray Diffraction Studies on MBE-Grown p-ZnTe/n-CdTe Heterojunctions for Solar Cell Applications
    Autorzy:
    Wichrowska, K.
    Domagala, J.
    Wosinski, T.
    Chusnutdinow, S.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1375736.pdf
    Data publikacji:
    2014-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.05.cp
    81.05.Dz
    81.15.Hi
    88.40.jm
    Opis:
    High-resolution X-ray diffractometer was used to study structural quality, lattice parameters and misfit strain in p-ZnTe/n-CdTe heterojunctions grown by the molecular-beam epitaxy technique on two different (001)-oriented substrates of GaAs and CdTe. The X-ray diffractometer results indicate that the CdTe layers, grown on lattice mismatched GaAs substrate, are partially relaxed, by the formation of misfit dislocations at the interface, and display residual vertical strain of the order of $10^{-4}$. The presence of threading dislocations in the layers effectively limits the efficiency of solar energy conversion in the investigated heterojunctions. Homoepitaxially grown CdTe layers, of much better structural quality, display unexpected compressive strain in the layers and the relaxed lattice parameter larger than that of the substrate. Possible reasons for the formation of that unusual strain are discussed.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 5; 1083-1086
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deep Electron Traps in CdTe:In Films Grown by Molecular Beam Epitaxy
    Autorzy:
    Żakrzewski, A. K.
    Dobaczewski, L.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934051.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.55.Ln
    73.61.Ga
    Opis:
    N-type indium doped CdTe grown on n$\text{}^{+}$-GaAs by molecular beam epitaxy has been studied by the standard deep level transient spectroscopy and the isothermal Laplace-transform deep level transient spectroscopy. It was found that the Cd/Te flux ratio strongly influences the deep level transient spectroscopy results. The unusual temperature dependence of the electron emission rate in films grown at nearly stoichiometric conditions may point out that the observed defect is resonant with the conduction band.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 961-964
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Identification of Optical Transitions from CdTe and CdMnTe Quantum Dots Embedded in ZnTe Nanowires
    Autorzy:
    Szymura, M.
    Kłopotowski, Ł.
    Wojnar, P.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399096.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Et
    78.67.Uh
    78.67.Hc
    Opis:
    We study photoluminescence properties of CdTe and CdMnTe quantum dots embedded in ZnTe nanowires. The nanowires were grown by molecular beam epitaxy, applying the vapor-liquid-solid growth mechanism. Linear polarization anisotropy measurements allow us to assess that the excitonic transitions originate from a single nanowire. We identify the optical transitions by comparing observed spectroscopic shifts with the universal emission pattern from the epitaxial CdTe dots. We support this identification by analyzing the photoluminescence intensity dependence on excitation power.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 824-826
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Native Deep-Level Defects in MBE-Grown p-Type CdTe
    Autorzy:
    Olender, K.
    Wosiński, T.
    Mąkosa, A.
    Dłużewski, P.
    Kolkovsky, V.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492964.pdf
    Data publikacji:
    2011-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Gs
    68.37.Lp
    61.72.J-
    61.72.Lk
    Opis:
    Deep-level transient spectroscopy was used to study the defect levels in p-type CdTe layers grown by the molecular-beam epitaxy technique on lattice-mismatched GaAs substrates. In our measurements we have observed five hole traps. Two of the traps, displaying exponential capture kinetics, have been assigned to native point defects, the Cd vacancy and a complex formed of Cd vacancy and Te antisite, produced in the CdTe layers during their growth. The other two traps have been attributed to electronic states of threading dislocations on the ground of their logarithmic capture kinetics. The last trap, which was observed only when the investigated space charge region was close to the metal-semiconductor interface, has been ascribed to surface states.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 5; 946-949
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mechanical and Electrical Properties, of ZnO-Nanowire/Si-Substrate Junctions Studied by Scanning Probe Microscopy
    Autorzy:
    Aleszkiewicz, M.
    Fronc, K.
    Wróbel, J.
    Klepka, M.
    Wojtowicz, T.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047440.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.37.Ef
    68.37.Ps
    68.65.La
    73.21.Hb
    78.67.Lt
    Opis:
    Scanning tunneling spectroscopy was used to check the tunneling I-V characteristics of junctions formed by n-ZnO nanowires deposited on Si substrates with n- and p-type electrical conductivity (i.e. n-ZnO nanowire/n-Si and n-ZnO nanowire/p-Si junctions, respectively). Simultaneously, several phenomena which influence the measured I-V spectra were studied by atomic force microscopy. These influencing factors are: the deposition density of the nanowires, the possibility of surface modification by tip movement (difference in attraction forces between nanowires and the p-Si and n-Si) and the aging of the surface.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 255-260
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature Dependence of Exciton and Trion States in CdTe Quantum Well at High Magnetic Fields
    Autorzy:
    Andronikov, D.
    Platonov, A.
    Crooker, S.
    Barrick, T.
    Karczewski, G.
    Kochereshko, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/2043711.pdf
    Data publikacji:
    2005-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.Ji
    73.21.Fg
    78.55.Et
    78.67.De
    Opis:
    Temperature dependent photoluminescence and reflectivity spectra of excitons, singlet and triplet states of trions were studied in CdTe-based quantum wells at high magnetic fields. Interesting features of the exciton and trion spectral lines with altering temperatures are explained by analyzing the thermal population and the kinetics of the exciton-electron-trion energetic system.
    Źródło:
    Acta Physica Polonica A; 2005, 108, 4; 653-660
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    High Mobility 2D Electron Gas in CdTe/CdMgTe Heterostructures
    Autorzy:
    Karczewski, G.
    Jaroszyński, J.
    Kutrowski, M.
    Barcz, A.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968126.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.40.Hm
    Opis:
    We report on iodine doping of molecular beam epitaxy (MBE)-grown Cd(Mn)Te quasi-bulk films and modulation-doped CdTe/Cd$\text{}_{1-y}$Mg$\text{}_{y}$Te two-dimensional (2D) single quantum well structures. Modulation doping with iodine of CdTe/Cd$\text{}_{1-y}$Mg$\text{}_{y}$Te structures resulted in fabrication of a 2D electron gas with mobility exceeding 10$\text{}^{5}$ cm$\text{}^{2}$/(V s). This is the highest mobility reported in wide-gap II-VI materials.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 829-832
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetic Force Microscopy Study of $Zn_{1-x}Co_{x}O$ Nanowires Grown by Rapid Thermal Evaporation
    Autorzy:
    Aleszkiewicz, M.
    Fronc, K.
    Aleszkiewicz, P.
    Zaleszczyk, W.
    Dziawa, P.
    Wojciechowski, T.
    Wojtowicz, T.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791327.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.37.Rt
    62.23.Hj
    Opis:
    In this work we studied domain structure of $Zn_{1-x}Co_{x}O$ nanowires which are single arms of tetrapode crystals. The as-grown material exhibits hysteretic behavior even at room temperature as revealed by SQUID mesurements. In order to get insight into the magnetic properties of individual tetrapodes they were dismembered into nanowires of nanometric diameters, deposited on a flat substrate and imaged by magnetic force microscopy. A magnetic interaction between the magnetic force microscopy probe and single nanowires has been detected which confirms that nanometric volume of the material possesses a magnetic moment. The magnetic force microscopy contrast is attractively independent of the tip magnetization direction which indicates that shape anisotropy of nanowires is not strong enough to prevent occurrence of tip-induced magnetic field disturbance.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 865-867
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Recombination Processes in Doped CdTe/CdMnTe Multiple Quantum Well Structures Grown by Molecular Beam Epitaxy
    Autorzy:
    Godlewski, M.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968089.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    78.55.Et
    Opis:
    An influence of doping level on exciton properties in n-doped multiple quantum well structures of CdTe/CdMnTe is studied for multiple quantum well structures prepared in the way that donor (indium) concentration changes within the length of the sample. We show that the formation scenario for neutral donor bound excitons in low-dimensional structures can be different from that observed in bulk samples. We further show that in the case of such quantum well structures we can selectively excite either photoluminescence emission of localized or donor bound excitons, which is a consequence of surprisingly weak energy transfer link between two types of excitonic transitions.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 757-760
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Dynamics in ZnTe Based Semimagnetic Semiconductors and CdMnTe Quantum Wells
    Autorzy:
    The Khoi, Nguyen
    Gaj, J.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Demianiuk, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952068.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.Pp
    78.66.Hf
    73.20.Dx
    Opis:
    Inelastic scattering of excitons on LO phonons in ZnTe based bulk semimagnetic semiconductors with low concentration of paramagnetic ions (Mn$\text{}^{2+}$, Fe$\text{}^{2+}$ and Cr$\text{}^{2+}$) was studied. A polarization degree of the LO phonon Raman lines was measured as a function of the exciton splitting in a magnetic field, and allowed us to determine the polarization lifetime (polariton flight time). A similar method was used to investigate multiple Mn$\text{}^{2+}$ spin-flip scattering in CdMnTe quantum well. The cascade model seems to be not adequate to interpret the dependence of the polarization degree on the order of scattering.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 899-902
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Quantum Hall Ferromagnet in Magnetically-Doped Quantum Wells
    Autorzy:
    Andrearczyk, T.
    Jaroszyński, J.
    Wróbel, J.
    Karczewski, G.
    Wojtowicz, T.
    Papis, E.
    Kamińska, E.
    Piotrowska, A.
    Popović, D.
    Dietl, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2036881.pdf
    Data publikacji:
    2003-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.43.Nq
    72.25.Dc
    73.61.Ga
    75.50.Pp
    Opis:
    The article reviews our recent studies on quantum Hall ferromagnetism in diluted magnetic semiconductors. We carried out magnetoresistance studies on modulation-doped, gated heterostructures of (Cd,Mn)Te/(Cd,Mg)Te:I. We put into evidence the formation of Ising quantum Hall ferromagnet with Curie temperature T$\text{}_{C}$ as high as 2 K. Quantum Hall ferromagnetism is manifested by anomalous magnetoresistance maxima. Moreover, magnitude of these spikes depends dramatically on the history of the sample, shows hysteresis when either magnetic field or gate voltage are swept, stretched-exponential time evolution characteristic of glassy systems, and strong Barkhausen noise. Our study suggests that these metastabilities stem from the slow dynamics of ferromagnetic domains.
    Źródło:
    Acta Physica Polonica A; 2003, 104, 2; 93-102
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectroscopy of Indirect Excitons in Vertically Stacked CdTe Quantum Dot Structures
    Autorzy:
    Kukliński, K.
    Kłopotowski, Ł.
    Fronc, K.
    Wojnar, P.
    Wojciechowski, T.
    Czapkiewicz, M.
    Kossut, J.
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1492851.pdf
    Data publikacji:
    2011-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Gs
    78.67.Hc
    32.60.+i
    Opis:
    We show that by means of an electric field we can tune the energy levels in vertical quantum dot pairs and study transitions related to recombination of direct and indirect excitons. With decreasing the reverse bias, we observe both the blue- and red-shifted indirect exciton transitions. Based on the band profile of our device, we conclude that the former corresponds to the recombination of the electron and hole localized in the top and the bottom dot, respectively and the latter is related to the recombination of the electron and hole localized in the bottom and the top dot, respectively.
    Źródło:
    Acta Physica Polonica A; 2011, 120, 5; 856-858
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetization Dynamics of a (Cd,Mn)Te Quantum Well in Pulsed Magnetic Field
    Autorzy:
    Kobak, J.
    Goryca, M.
    Kossacki, P.
    Golnik, A.
    Karczewski, G.
    Wojtowicz, T.
    Gaj, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791344.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    71.70.Gm
    78.55.Et
    75.75.-c
    Opis:
    In this paper we present studies of magnetization relaxation in a (Cd,Mn)Te quantum well containing 3.2% of Mn, after a pulse of magnetic field. The relaxation was found to be very fast, with dominant component faster than 10 ns. Upon application of static magnetic field the relaxation does not slow down, in contrast with the behavior of very diluted quantum wells or bulk material.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 907-908
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cold and Hot Excitons in CdMnTe/CdMgTe Quantum Wells in Strong Excitation Regime and External Magnetic Field
    Autorzy:
    Trajnerowicz, A.
    Golnik, A.
    Kossacki, P.
    Bardyszewski, W.
    Wiater, M.
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791298.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.De
    71.35.Lk
    78.47.-p
    Opis:
    Systematic studies of neutral heavy-hole excitonic line energy changes in a strong excitation regime were carried out by means of a pump-probe method for quantum wells containing a 2D gas of free holes. Energy shift of $X_{e1hh1}$ line was analyzed for different excitation energies at fixed delay between pump and probe pulses, also under external magnetic field. It was observed that this shift depends not only on the density of created excitons but also directly on the pump energy. In co-polarization configuration for excitation energy below an absorption resonance the energetic blue shift rises linearly with the elevated exciton density (localized excitons are created). For energies slightly above the resonance, the blue shift diminishes dramatically in spite of high exciton density present (delocalized excitons are created). Model absorption calculations are in qualitative agreement with the experimental data.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 849-851
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Non-Ohmic Conductivity of High Resistivity CdTe
    Autorzy:
    Łusakowski, J.
    Szczytkowski, J.
    Szadkowski, K.
    Kamińska, E.
    Piotrowska, A.
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933850.pdf
    Data publikacji:
    1995-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.80.-r
    Opis:
    Conductivity measurements were carried out at room temperature on samples of nominally undoped Bridgman, bulk crystals and MBE-grown layers of CdTe. The samples were equipped with indium contacts which made it possible to determine the voltage distribution along the path of the current flow. The results show that for both types of CdTe almost all of the applied voltage drops in the vicinity of the positively biased contact. The resistance of the samples was shown not to depend on the distance between the pads. The results agree with predictions of model of current injection into semiconductors with deep traps.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 4; 803-806
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Unusual Time Dependence of Magnetization Relaxation in MBE Grown Epilayer of CdMnTe
    Autorzy:
    Witowski, A. M.
    Moll, H. P.
    Wyder, P.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934049.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.60.Wm
    76.30.Fc
    Opis:
    The temporal behavior of the magnetization due to the spin-lattice relaxation for bulk and MBE grown epilayer of CdMnTe is compared. The time dependence of the epilayer magnetization changes (dM/dt) is nonmonotonic. After the main part, a second structure appears. It can be explained only by the assumption of energy storage and a delayed additional rise of specimen temperature. The nature of the storage is unknown.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 953-956
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical Characterization of MBE-Grown Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Layers by Raman Spectroscopy
    Autorzy:
    Szuszkiewicz, W.
    Dynowska, E.
    Janik, E.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Jouanne, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1945228.pdf
    Data publikacji:
    1996-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    63.20.-e
    75.50.Pp
    78.30.-j
    Opis:
    In this paper we discuss a possibility of an optical characterization of thin semiconductor epilayers by Raman scattering measurements. As an example zinc blende Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te epilayers (0.66 ≤ x ≤ 1.0) have been grown by molecular beam epitaxy method and investigated by Raman scattering and X-ray diffraction. Information resulting from both methods is compared and discussed.
    Źródło:
    Acta Physica Polonica A; 1996, 89, 3; 335-340
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Magneto-Optical Study on Single Quantum Wells, Cd$\text{}_{1-x}$Zn$\text{}_{x}$Te/Cd$\text{}_{1-x'-y}$Zn$\text{}_{x}$'Mn$\text{}_{y}$Te
    Autorzy:
    Takeyama, S.
    Grabecki, G.
    Adachi, S.
    Takagi, Y.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934045.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.-m
    78.20.Ls
    78.66.Hf
    Opis:
    Four-single quantum wells composed of the ternary non-magnetic compounds Cd$\text{}_{0.93}$Zn$\text{}_{0.07}$Te (well width = 13, 19, 40, 90 Å), separated by the quaternary magnetic-compound Cd$\text{}_{0.48}$Zn$\text{}_{0.04}$Mn$\text{}_{0.48}$Te on (100)GaAs substrate were grown by MBE, and exhibited clear and distinctive photoluminescence lines corresponding to each quantum well. Double luminescence peaks with closely spaced within one well were observed from 90 Å and 40 Å quantum wells. Temperature and magnetic-field study revealed characteristic luminescence features associated with a bound exciton near the interface rather than with one monolayer fluctuation.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 945-948
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Excitons and Trions in Modulation Doped Structures in High Magnetic Fields
    Autorzy:
    Kochereshko, V.
    Andronikov, D.
    Platonov, A.
    Crooker, S.
    Barrick, T.
    Karczewski, G.
    Tronc, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2038321.pdf
    Data publikacji:
    2004-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Et
    71.35.-y
    78.20.Ls
    78.40.Fy
    Opis:
    Photoluminescence spectra of modulation-doped CdTe/CdMgTe quantum well structures containing two-dimensional electron gases of low, moderate and high electron concentrations were studied in high magnetic fields up to 45 T. The recombination line of triplet trion state was found in the spectra. A model calculation of photoluminescence spectra in magnetic fields, which takes into account singlet and triplet trion states, was carried out. It was shown that the dark triplet becomes observable in photoluminescence spectra because it becomes the only recombination channel when the formation of the singlet trion state is suppressed by magnetic fields.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 3; 319-328
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Interface-Induced Disorder on Classical and Quantum Conductivity of CdTe:IN Epitaxial Layers
    Autorzy:
    Łusakowski, J.
    Karpierz, K.
    Grynberg, M.
    Karczewski, G.
    Wojtowicz, T.
    Contreras, S.
    Callen, O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968369.pdf
    Data publikacji:
    1997-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.50.Jt
    73.61.Ga
    Opis:
    An influence of disorder originated from the substratelayer interface on electrical properties of CdTe:In layers was investigated by means of the Hall effect and magnetoresistance measurements at low temperatures. An estimation of a scattering rate due to interface-induced disorder is given. Characteristic features of a magnetic field dependence of magnetoresistance are explained by an influence of quantum interference of scattered electron waves both in the hopping and the free electron conductivity regimes.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 5; 911-914
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Excitonic Energy Shifts in CdMnTe/CdMgTe Quantum Wells under Resonant Excitation in Presence of 2D Carrier Gas
    Autorzy:
    Trajnerowicz, A.
    Golnik, A.
    Kossacki, P.
    Bardyszewski, W.
    Wiater, M.
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811999.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.De
    71.35.Lk
    78.47.-p
    Opis:
    Systematic studies of amplitude and energy changes of excitonic lines in a strong excitation regime were carried out by a pump-probe method. The series of samples containing quantum wells with well width from 80 Åto 140 Åwas investigated. One 80 Åsample was n-doped with iodine, the rest of the quantum wells were intentionally undoped but contained a 2D gas of free holes. Its density could be varied by changing an intensity of additional illumination. The resonant creation of high population of e1hh1 excitons causes the energetic blue shift of the same due to interactions between excitons. The blue shifts did not depend on the concentration of 2D gas of carriers whereas it did depend on the power of excitation beam. Model calculations of absorption show qualitative agreement with the experimental data.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1403-1409
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conductance Fluctuations in Quantum Wires of n-CdTe and n-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
    Autorzy:
    Jaroszyński, J.
    Wróbel, J.
    Sawicki, M.
    Skośkiewicz, T.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Dietl, T.
    Kamińska, E.
    Papis, E.
    Barcz, A.
    Piotrowska, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934061.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.15.Rn
    73.61.Ga
    73.20.Fz
    Opis:
    We present millikelvin studies of magnetoconductance in submicron wires of In-doped n$\text{}^{+}$-CdTe and n$\text{}^{+}$-Cd$\text{}_{0.99}$Mn$\text{}_{0.01}$Te epilayers. Weak-field magnetoresistance which arises from quantum localization as well as universal conductance fluctuations have been observed. The exchange coupling to magnetic impurities is shown to decrease the correlation field of the fluctuations. This novel effect is interpreted by invoking a new driving mechanism of the magnetoconductance fluctuations - the redistribution of the electrons between energy levels of the system, induced by the giant s-d spin-splitting of the electronic states.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 1000-1004
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Magnetic Polaron Features in Photoluminescence Excitation Spectra of CdTe/(CdMn)Te Quantum Wells with High Mn Contents
    Autorzy:
    Mackh, G.
    Ossau, W.
    Yakovlev, D. R.
    Landwehr, G.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933923.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.+z
    78.55.Et
    Opis:
    Exciton magnetic polarons are studied in CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te (0.4 ≤ x ≤ 0.8) quantum wells. The magnetic polaron formation leads to the appearance of an additional line in the photoluminescence excitation spectra, which can be employed to determine the Zeeman splittings more exactly than by using the free exciton peak. We find an overall increase in the polaron energy with increasing x in the whole range of Mn contents studied.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 849-852
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    MBE Growth and Characterization of Cubic MnTe(111) on BaF$\text{}_{2}$ Substrates
    Autorzy:
    Janik, E.
    Wojtowicz, T.
    Dynowska, E.
    Bąk-Misiuk, J.
    Domagała, J.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934056.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.Pp
    68.55.Bd
    68.55.Jk
    Opis:
    We report on growth by molecular beam epitaxy of cubic MnTe(111) layers on BaF$\text{}_{2}$ (111) substrates. Layers as thick as 0.2-1.0 μm were grown. Basic characterization by X-ray diffraction shows that the cubic crystal structure is deformed to orthorhombic symmetry.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 982-984
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of Optical Properties of CdTe/CdMnTe Quantum Wells Grown by Molecular Beam and Atomic Layer Epitaxy
    Autorzy:
    Godlewski, M.
    Kopalko, K.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952470.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.+z
    78.47.+p
    78.55.Et
    Opis:
    Optical properties of a series of CdTe/CdMnTe multi quantum well structures grown with MBE and ALE (CdTe quantum wells only) methods are compared. Based on the results of the photoluminescence experiments we conclude that the ALE growth leads to a different lateral scale of quantum well width fluctuations, which results in different exciton properties in two multi quantum well systems studied. In the wells grown with ALE method excitons are less localized. They can migrate in a quantum well plane between quantum well regions varying in thickness by 1 monolayer.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 1012-1016
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization and Selected Physical Properties of CdTe/MnTe Short Period Strained Superlattices
    Autorzy:
    Szuszkiewicz, W.
    Dynowska, E.
    Bąk-Misiuk, J.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Jouanne, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952708.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    63.20.-e
    78.30.Fs
    Opis:
    Phonon excitations in (CdTe)$\text{}_{12}$/(MnTe)$\text{}_{n}$ (100) superlattices (n=2, 4, 8) were investigated at 295 K and 25 K with the use of Raman scattering. From the "folded" phonon frequencies the elastic constant c$\text{}_{11}$ value for MnTe was estimated. The strain arising from lattice mismatch (determined by X-ray diffraction) results in shifts of MnTe and CdTe "confined" LO phonon frequencies. For the precise determination of LO phonon dispersions an additional shift due to Mn diffusion at the CdTe/MnTe interface should be taken into account.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 1090-1094
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Properties in CdTe/CdMnTe Quantum Well Structures with Strong Localization Effects
    Autorzy:
    Godlewski, M.
    Narkowicz, R.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969075.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.-y
    71.55.Jv
    73.20.Mf
    Opis:
    Strong localization effects present in quantum well structures of CdTe/ CdMnTe noticeably affect exciton dynamics and strength and character of exciton-phonon interaction. We show that the temperature dependences of the PL linewidth, PL peak wavelength and PL decay time strongly deviate from those expected for Wannier-excitons in structures with atomically smooth interfaces.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 317-320
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reduction of the Optical Losses in CdTe/ZnTe Thin-Film Solar Cells
    Autorzy:
    Chusnutdinow, S.
    Pietruszka, R.
    Zaleszczyk, W.
    Makhniy, V.
    Wiater, M.
    Kolkovsky, V.
    Wojtowicz, T.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1375701.pdf
    Data publikacji:
    2014-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.15.Hi
    73.61.Ga
    85.60.Dw
    88.40.jm
    Opis:
    We report on reduction of optical losses in n-CdTe/p-ZnTe thin-film solar cells grown by molecular beam epitaxy. The investigated thin-film devices were grown from elemental sources on monocrystalline, semi-insulating, (100)-oriented GaAs substrates. The optical losses have been reduced by a texturing of the device surface and by depositing of a ZnO antireflection coating. Current-voltage and spectral characteristics of the investigated p-ZnTe/n-CdTe solar cells depend significantly on the preparation of the surface of the ZnTe window. We describe a procedure of chemical etching of the ZnTe window leading to surface texturing. A ZnO layer of proper thickness deposited by low-temperature atomic layer deposition technique on the ZnTe surface forms an effective antireflection coating that leads to the reduction of optical losses. Due to reduction of the optical losses we observe increase of the short-circuit current, $J_{SC}$, by almost 60% and of the energy conversion efficiency by 44%.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 5; 1072-1075
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Single-Photon Emission from a Highly Excited CdTe Quantum Dot
    Autorzy:
    Nowak, S.
    Goryca, M.
    Kazimierczuk, T.
    Gaj, J.
    Golnik, A.
    Kossacki, P.
    Wojnar, P.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811969.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.21.La
    78.55.Et
    78.67.-n
    78.47.-p
    Opis:
    Time-resolved correlation measurements were performed to examine the statistics of photon emission from a single quantum dot at high excitation levels. The range of strong powers was determined by the saturation of intensity of excitonic lines. The significant contribution of pulsed background luminescence forced us to sophisticated analysis of the photoluminescence spectra. For quantum dots grown in the Stranski-Krastanov mode, one-photon emission was found to a good approximation. Fluctuation type quantum dots exhibit a significant level of multiphoton emission.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1273-1278
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetic Characterization of Molecular Beam Epitaxy Grown $Cd_{1-x}$Mn$\text{}_{x}$Te Structures
    Autorzy:
    Sawicki, M.
    Kolesnik, S.
    Wojtowicz, T.
    Karczewski, G.
    Janik, E.
    Kutrowski, M.
    Żakrzewski, A.
    Dynowska, E.
    Dietl, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1931934.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.-y
    75.50.Rr
    75.50.Ee
    Opis:
    The paper reports on the application of SQUID magnetometry to probe magnetic ion distribution in epilayers and at interfaces of diluted magnetic semiconductors. We present also new results on the possible influence of the magnetic confinement on the formation of the spin-glass phase, and on antiferromagnetic phase transition in zinc-blende MnTe.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 169-172
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Magnetization Steps in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Observed in Coherent Transport
    Autorzy:
    Jaroszyński, J.
    Dietl, T.
    Wróbel, J.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Maude, D. K.
    van der Linden, P.
    Portal, J. C.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968114.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.15.Rn
    73.61.Ga
    73.20.Fz
    Opis:
    Magnetoconductance measurements on submicron wires of n$\text{}^{+}$-Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te were carried out up to 27 T and down to 100 mK. The inverse correlation field of the universal conductance fluctuations is found to increase abruptly in the vicinity of the magnetization steps due to Mn pairs in CdMnTe. No such effect is observed in similar wires of CdTe. These findings support a recent model, according to which the correlation field of the universal conductance fluctuations in magnetic systems is inversely proportional to the magnetic susceptibility of the localized spins.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 797-800
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spatial Correlations of Donor Charges in MBE CdTe
    Autorzy:
    Suski, T.
    Wiśniewski, P.
    Litwin-Staszewska, E.
    Wasik, D.
    Przybytek, J.
    Baj, M.
    Karczewski, G.
    Wojtowicz, T.
    Zakrzewski, A.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934021.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.80.Ey
    71.55.Gs
    Opis:
    We present experimental evidence that at high pressures indium donors in CdTe localize electrons in spatially correlated manner. We have studied Hall mobility, μ$\text{}_{H}$, as a function of electron concentration, n$\text{}_{H}$, at T=77 K. Changes of n$\text{}_{H}$ have been achieved by two methods. High pressure freeze-out of electrons onto localized states of In-donors leads to the mobility enhancement with respect to the situation when n$\text{}_{H}$ has been modified by means of a subsequent annealing of the sample. As a result, depending on the degree of spatial correlations in the impurity charges arrangement, different values of μ$\text{}_{H}$ correspond to the same value of n$\text{}_{H}$. The variation of mobility with electron concentration suggests that the localized state of In-donor represents likely negatively charged DX state.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 929-932
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    (120)-Oriented CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy
    Autorzy:
    Kutrowski, M.
    Karczewski, G.
    Cywiński, G.
    Surma, M.
    Grasza, K.
    Łusakowska, E.
    Kossut, J.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952037.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    78.55.Et
    Opis:
    We report on the MBE growth and magnetooptical studies of (120)-oriented CdTe/CdMnTe quantum well structures. The quality of structures, as evaluated by the photoluminescence line width, was as good as that of the best structures grown in ⟨100⟩ direction. No spin splitting enhancement, expected theoretically, due to the reduction of the antiferromagnetic interaction between Mn ions in CdTe/CdMnTe digital alloy quantum wells grown along ⟨120⟩ direction was observed.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 879-882
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Dynamics in CdTe/CdMnTe Multiquantum Well Structures Grown by Molecular Beam. Epitaxy on GaAs Substrate
    Autorzy:
    Godlewski, M.
    Koziarska, B.
    Suchocki, A.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Bergman, J.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934057.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.60.-p
    78.47.+p
    73.20.Fz
    71.35.+z
    Opis:
    The results of picosecond photoluminescence kinetics of four different CdTe/CdMnTe multiquantum well structures grown by MBE on GaAs substrates are presented. The experimental results show that excitons in CdTe quantum wells are strongly localized by potential fluctuations. Photoluminescence decay times of the localized excitons are considerably shorter (about 120 ps) than those reported for free or quasi-free excitons. An influence of Mn in the barriers on exciton properties is demonstrated. For narrow quantum wells as well as for the multiquantum well structure with the highest Mn mole fraction the excitons migrate during their decay to the states with a lower potential energy. Longer decay times are observed for quasi-localized excitons. We show also that for strongly localized excitons the energy transfer between localized and donor bound excitons is less efficient.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 985-989
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Hot Photoluminescence in CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy
    Autorzy:
    Godlewski, M.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Holtz, P. O.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968096.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    78.55.Et
    Opis:
    A step-like emission is observed for CdTe/CdMnTe structures δ-doped with In. The new photoluminescence cannot be explained by neither the Raman process nor by the "ordinary" hot photoluminescence. We propose that magnetic interactions are responsible for the new photoluminescence appearing due to a dramatic increase in a thermalization time of hot excitons.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 765-768
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optically Detected Magnetic Resonance of Excess Electrons in CdTe/(Cd,Mg)Te Quantum Wells
    Autorzy:
    Hu, C. Y.
    Ossau, W.
    Yakovlev, D. R.
    König, B.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969094.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    76.70.Hb
    71.35.-y
    71.35.Ji
    Opis:
    The spin resonance of excess electrons is observed with the detection either on the neutral or the negatively charged exciton X$\text{}^{-}$ emission in type I CdTe/(Cd,Mg)Te quantum wells with excess electrons of low density. It is found that the electron spin-dependent and electron spin-conserving formation and recombination of X$\text{}^{-}$ make the optical detection of the spin resonance of excess electrons feasible. For the first time, optically detected magnetic resonance is used to study fast optical transition processes in the nanosecond timescale where the microwave-induced magnetic transition rate is much lower than the optical transition rate.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 351-354
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ genotypu i modelowych stresorów na wskaźniki fizjologiczne u tuczników
    Vlijanie genotipa i modelnykh stressorov na fiziologicheskie pokazateli otkormochnykh svinej
    The influence of genotype and model stress factors on physiological indices in fattened pigs
    Autorzy:
    Dziewiecki, C.
    Kolataj, A.
    Piekarzewska, A.
    Karczewski, D.
    Zebrowski, Z.
    Blicharski, T.
    Szymanowska, B.
    Tyrolczyk, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/801984.pdf
    Data publikacji:
    1990
    Wydawca:
    Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
    Tematy:
    genotyp
    stresor modelowy
    wskazniki fizjologiczne
    tuczniki
    syndrom stresowy swin
    landrace
    duroc
    uboj
    wydajnosc rzezna
    Opis:
    Соотвeтствубщие исследования охватывали трехпородные помеси свиней: (польской белой вислоухой х крупной белой польской) х нeмецкой белой вислоухой (группа I) и (польской белой вислоухой х крупной белой польской) х дюрок (группа II). В рамках группы I одна погруппа (10 голов) была подвергнута однонедельному голоданию. Группа II oзватывала сверх того подгруппу подвергнутую чрезмерной скученности в станке. Среди исследуемых физиологических признаков наблюдалась высокосущественная разница (50%) между контрольными подгрупцамн обоих генотипов на уровне мышечного гликогена в пользу группы I. Таких разниц не обнаружено среди исследуемых параметров плазмы. Голодание в обеих группах привело к высокосущественному повышению уровня холестерола в плазме; существенное снижение уровня глюказа наблюдалось только в группе I. Голодание не оказывало существенного влияния на уровень белка ни в одной из исследуемых групп откормочников, равно как и не изменялся уровень общих липидов. В рамках последней группы соединений отдельные фракции представлялись различно: уровень свободных жирных кислот повысился 3-4 раза у обеих групп, тогда как концентрация фракции триглицеридов не изменилась в группе I, повышаясь высокосущественно (на 0,20 мМ/л) в группе I у помесей (польская белая вислоухая х крупная белая польская) x дюрок. Активность альдолазы не изменилась ни в одной группе, тогда как активность фосфофруктокиназы не изменилась в группе I, а в группе II повысилась высокосущественно на 50%. Голодание привело к высокосущественному снижению уровня гликогена как в почени так и в свелетных мышцах в обеих исследуемых генетических группах: в группе I трехкратно, в группе II двухкратно. Не установлено заметного влияния степени скученности в станке на исследуемые физиологические параметры. Полученные результаты указывают на различность физиологической реакции в зависимости от генотипа откормочников.
    The investigations covered the following cross-breeds: (Polish Landrace x Polish Large White) x German Landrace (group I) and (Polish Landrace x Polish Large White) x Duroc (group II). Group I was divided into 2 subgroups, one of which was subjected to a week of fasting. Within group II there was created a third subgroup which was subjected to overcrowding. Among the physiological changes examined there occurred a highly significant difference in the level of muscle glycogen (50%) between the control groups (in favour of the group I). Among the serum parameters examined no such differences were observed. After fasting in both groups there occurred a highly significant increase in the plasma cholesterol. A significant decrease in the level of glucose was observed only in the group I. Fasting did not exert any significant effect on the level of proteins in either group, similarly as it did not change the level of total lipids. However, within this last group of compounds individual fractions reacted differently; the level of WKT increased 3-4 times in both groups while the level of triglicerides did not change in the group I, but in the crossbreds with Duroc it increased highly significantly (by 0.20 mM/1). The activity of aldolase did not change in either group, while the activity of PHI, unchanged in the group I, increased significantly in the group II (by 50%). Fasting led to a highly significant lowering of the level of glycogen in the liver and in the skeletal muscles of both genetic groups: thrice in the group I and twice in the group II. There was observed no distinct influence of overcrowding on the physiological parameters examined. The results obtained indicate a differentiated physiological reaction depending on the genotype of the pigs.
    Źródło:
    Zeszyty Problemowe Postępów Nauk Rolniczych; 1990, 384
    0084-5477
    Pojawia się w:
    Zeszyty Problemowe Postępów Nauk Rolniczych
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature Dependence of Energy Gap of Highly Concentrated Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te(0.6 < x ≤ 1.0) Epilayers
    Autorzy:
    Stachow, A.
    Mac, W.
    Nguyen, The Khoi
    Twardowski, A.
    Karczewski, G.
    Janik, E.
    Wojtowicz, T.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1934002.pdf
    Data publikacji:
    1995-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.40.Fy
    75.25.+z
    78.20.Ls
    Opis:
    The temperature dependence of the energy gap of MBE grown Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te (0.6 < x ≤ 1.0) was measured for 2 K ≤ T ≤ 200 K and B ≤ 5 T. The results are interpreted in the frames of the model predicting that the exchange contribution to the band edge shift is proportional to the product of the magnetic susceptibility and the temperature.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 5; 913-916
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dimensional Crossovers in Magnetoresistance of Submicron Films and Wires of CdTe:In
    Autorzy:
    Jaroszyński, J.
    Wróbel, J.
    Sawicki, M.
    Skośkiewicz, T.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Dietl, T.
    Kamińska, E.
    Papis, E.
    Piotrowska, A.
    Duś, R.
    Nowakowski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952536.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Jv
    Opis:
    We present millikelvin studies of magnetoresistance for epitaxial films and wires of CdTe:In. In comparison to the data with theoretical predictions for the weakly localized regime we put into the evidence the presence of the temperature-induced dimensional crossovers in the studied systems. Our measurements probe the electron phase-breaking rate and indicate that the main dephasing mechanism arises from electron scattering from thermal fluctuations of three- or two-dimensional electron liquid.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 1027-1031
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of Spin-Glass Transition in Semimagnetic Quantum Wells Based on Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te by Means of Optical Spectroscopy
    Autorzy:
    Zehnder, U.
    Yakovlev, D. R.
    Ossau, W.
    Waag, A.
    Landwehr, G.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968455.pdf
    Data publikacji:
    1997-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.Ji
    78.55.Et
    Opis:
    The spin-glass transition in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te epitaxial layers and bulk samples with 0.24 ≤ x ≤ 0.43 and in quantum well structures on the basis of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te were investigated by means of optical spectroscopy. Reduction of dimensionality of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te layers down to the quasi-two-dimensional case realized in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te/Cd$\text{}_{1- y}$Mn$\text{}_{y}$Te heterostructures frustrates the spin-glass formation, which is in agreement with theoretical predictions. The spin-glass formation is also frustrated in the vicinity of interfaces between semimagnetic and nonmagnetic semiconductors in CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te quantum wells.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 5; 1075-1078
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmission SecondHarmonic Generation in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te at 1.064 µm
    Autorzy:
    Koziarska, B.
    Kowalczyk, L.
    Suchocki, A.
    Wojtowicz, T.
    Zakrzewski, A. K.
    Karczewski, G.
    Janik, E.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1873081.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.65.Ky
    68.70.+w
    Opis:
    Second harmonic generation, created by nanosecond Nd : YAG laser pulses at 1.064 µm with relatively low intensity in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te bulk crystals and thin layers was measured in transmission geometry. The effect practically occurs in a very thin surface layer of the material and it is used as a relatively straightforward method of layer quality characterization. It is shown that the angular dependence of the second harmonic generation intensity in thin layers of CdTe with good crystallographic (and optical) quality agrees very well with the theory in contrary to the samples with some distortions from the ideal structure which exhibits large distortions from the theory.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 423-426
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Atomic Force Microscopy Study of a Voltage Effect on CdZnTe Crystal Dimensions
    Autorzy:
    Aleszkiewicz, P.
    Wojciechowski, T.
    Fronc, K.
    Kolkovsky, V.
    Janik, E.
    Jakieła, R.
    Mycielski, A.
    Karczewski, G.
    Aleszkiewicz, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1811911.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.40.Ns
    73.61.Ga
    77.90.+k
    Opis:
    In this work we studied the influence of an external electric voltage on spatial dimensions of CdZnTe mixed crystals. In order to get an absolute magnitude of the sample thickness and to gain insight to the changes of lateral dimension, in quasi-bulk 3 μm thick CdZnTe layers grown by molecular beam epitaxy square craters were formed by ion sputtering in a secondary ion mass spectrometer. The vertical and lateral dimensions of the craters were studied by the atomic force microscopy. The atomic force microscopy measurement revealed that the thickness of the CdZnTe layer increases in a result of applying a single voltage pulse to the sample surface and decreases reversibly after applying reversely biased voltage. The voltage triggering was high enough to switch the conductivity state of the sample i.e., the effect of thickness change is accompanied by the effect of conductivity switching. The thickness change is significant, reaching several percents of the entire layer thickness.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1041-1047
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nonradiative Recombination Processes in (CdTe,CdCrTe)/CdMgTe Quantum Well Structures
    Autorzy:
    Godlewski, M.
    Ivanov, V.
    Zakrzewski, A. J.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968108.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.60.-p
    76.70.Hb
    Opis:
    Photoluminescence transitions in (CdTe,CdCrTe)/CdMgTe structure grown by molecular beam epitaxy are studied. Photoluminescence investigations show a very strong reduction of the photoluminescence intensity from chromium doped quantum wells. We explain this fact by a very efficient nonradiative recombination in the chromium-doped quantum wells. The present results indicate that the Auger-type energy transfer from excitons to chromium ions is responsible for the photoluminescence deactivation. The efficiency of this process is evaluated.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 781-784
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Two-Electron DX State in CdTe:In
    Autorzy:
    Skierbiszewski, C.
    Wiśniewski, P.
    Litwin-Staszewska, E.
    Suski, T.
    Wilamowski, Z.
    Zakrzewski, A. K.
    Karczewski, G.
    Jantsch, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952096.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.55.Gs
    73.61.Ga
    Opis:
    In this paper we investigate electron emission/capture from/to the DX state of indium in CdTe by means of high pressure freeze-out cycle and steady-state photo-conductivity experiments. The results indicate that the DX state is occupied by two electrons. A comparison with deep level transient spectroscopy data shows that two-electron emission occurs at low temperatures, while one-electron emission takes place at high temperatures.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 927-930
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spin-Related Spectroscopy of CdTe-Based Quantum Dots
    Autorzy:
    Gaj, J.
    Kazimierczuk, T.
    Goryca, M.
    Koperski, M.
    Golnik, A.
    Kossacki, P.
    Nawrocki, M.
    Wojnar, P.
    Karczewski, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1585136.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.67.Hc
    71.70.Gm
    75.75.+a
    78.55.Et
    Opis:
    This work contains a selection of our recent experimental results in the field of the spin-related spectroscopy of individual CdTe-based quantum dots. After a short description of the sample growth and experimental methods, optical measurements of the charge state dynamics are presented. Then the influence of in-plane anisotropy of the excitonic states of a quantum dot is discussed, followed by a description of experimental studies of information read-out and writing on quantum dot spin states. In particular, spin memory of a single $Mn^{++}$ ion embedded in a CdTe quantum dot is quantitatively assessed. In an outlook part, perspectives opened by recently developed ZnTe lattice-matched Bragg reflectors are discussed.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 795-799
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature Study of Photoluminescence from Deep CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Quantum Wells
    Autorzy:
    Kutrowski, M.
    Wojtowicz, T.
    Karczewski, G.
    Kopalko, K.
    Zakrzewski, A. K.
    Janik, E.
    Grasza, K.
    Łusakowska, E.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1876361.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    78.55.Et
    Opis:
    The photoluminescence studies in CdTe/CdMnTe quantum wells are reported in the temperature range 10-300 K. The MnTe concentration in the barriers is x = 0.3, 0.5, 0.63 and 0.68. Thus the potential wells in our samples are very deep, of the order of ≈ 800 meV in the conduction band and ≈ 200 meV in the valence band in the case of the x = 0.68 sample. In spite of the large lattice mismatch (related to high x value) between the wells and the barriers the observed line widths are as narrow as 2 meV in the case of 100 Å. Clear manifestations of internal strain are observed. In particular, the temperature coefficient of the luminescence energies shows strong dependence on the width of wells.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 500-504
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microwave-Induced Delocalization of Excitons in Ternary Compounds of II-VI and III-V Semiconductors
    Autorzy:
    Ivanov, V. Yu.
    Godlewski, M.
    Khachapuridze, A.
    Yatsunenko, S.
    Wojtowicz, T.
    Karczewski, G.
    Bergman, J. P.
    Monemar, B.
    Shamirzaev, T.
    Zhuravlev, K.
    Leonardi, K.
    Hommel, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035757.pdf
    Data publikacji:
    2003-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.35.Ji
    72.25.Rb
    76.70.Hb
    78.55.Et
    Opis:
    In this work we employ technique of optically detected cyclotron resonance for evaluation of the role of localization processes in CdTe/CdMnTe and CdMnTe/CdMgTe quantum well structures. From microwave-induced changes of excitonic emissions we evaluate magnitude of potential fluctuations (Stokes shift), correlate optically detected cyclotron resonance results with the results of time-resolved experiments and discuss nature of recombination processes in the limit of a strong localization.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 6; 559-566
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Exciton Transfer in Multiple Quantum Well Structures of CdTe/CdMnTe Grown by Molecular Beam Epitaxy
    Autorzy:
    Godlewski, M.
    Surma, M.
    Wilamowski, Z.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Holtz, P. O.
    Bergman, J. P.
    Monemar, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968091.pdf
    Data publikacji:
    1997-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.47.+p
    78.55.Et
    Opis:
    The direct evidence for the efficient transfer of excitons from 4 nm and 6 nm to 10 nm wide CdTe quantum wells is presented based on the results of photoluminescence and photoluminescence excitation investigation. Efficient transfer is observed for quantum wells separated by thick (50 nm) CdMnTe barriers containing 10% or 30% Mn fraction. A new mechanism of the transfer is proposed, which involves long range dynamic magnetic interactions between free/bound excitons and Mn ions in the CdMnTe barrier regions of the structure.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 4; 761-764
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Luminescence Decay in Deep Quantum Wells CdTe/Cd_{0.5}Mn_{0.5}Te at Room Temperature
    Autorzy:
    Kowalczyk, L.
    Fancey, S.
    Buller, G.
    Massa, J.
    Kutrowski, M.
    Janik, E.
    Karczewski, G.
    Wojtowicz, T.
    Zakrzewski, A.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1876908.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.66.Hf
    78.47.+p
    78.55.Et
    Opis:
    Time-resolved photoluminescence was used to study exciton recombination in deep CdTe/Cd_{0.5}Mn_{0.5}Te single quantum well. The width of the investigated well was 100 A. The study was performed at room temperature. The lifetime of the exciton determined in this work has a value comparable to that observed in shallow CdTe/Cd_{0.85}Mn_{0.15}Te quantum wells. A strong enhancement of the photoluminescence decay time with increasing intensity of the exciting laser beam is observed which is indicative of saturation of the non-radiative recombination centers.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 508-513
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Parabolic Quantum Wells
    Autorzy:
    Wojtowicz, T.
    Kutrowski, M.
    Cywiński, G.
    Dynowska, E.
    Karczewski, G.
    Kossut, J.
    Fiederling, R.
    Mackh, G.
    Zehnder, U.
    Ossau, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1952428.pdf
    Data publikacji:
    1996-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    78.55.Et
    Opis:
    We report on the growth and optical studies of II-VI semiconductor parabolic quantum wells made of Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te for a broad range of quantum well widths and Mn molar fractions x. Photoluminescence excitation spectra revealed several series of peaks equidistant in energy associated with interband optical transitions between harmonic oscillator levels. From the analysis of the spectra the valence band offset Q$\text{}_{hh}$ = 0.44±0.1 was determined for the CdTe/Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te system.
    Źródło:
    Acta Physica Polonica A; 1996, 90, 5; 977-980
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lattice Parameter Relaxation during MBE of ZnTe/Cd$\text{}_{1-x}$Zn$\text{}_{x}$Te/Cd$\text{}_{0.5}$Zn$\text{}_{0.5}$Te Buffer Layers by RHLED and HRTEM
    Autorzy:
    Kret, S.
    Karczewski, G.
    Zakrzewski, A.
    Dłużewski, P.
    Dubon, A.
    Wojtowicz, T.
    Kossut, J.
    Delamarre, C.
    Laval, J. Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933838.pdf
    Data publikacji:
    1995-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.16.Bg
    61.14.Hg
    68.35.-p
    Opis:
    The dynamics of the lattice relaxation processes were investigated using a reflection of a high energy electron diffraction analysis system during growth by molecular beam epitaxy of ZnTe/Cd$\text{}_{1-x}$Ζn$\text{}_{x}$Te/Cd$\text{}_{0.5}$Mn$\text{}_{0.5}$Te buffers on GaAs substrates. The variation of the lattice parameter recorded by the high energy electron diffraction during the growth was later confirmed by an analysis of high resolution transmission electron microscopy images. We report also on an observation of oscillations of the lattice parameter during the deposition of several first layers of ZnTe on CdTe.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 4; 795-798
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Novel CdTe/CdMgTe Graded Quantum Well Structures
    Autorzy:
    Wojtowicz, T.
    Kutrowski, M.
    Karczewski, G.
    Cywiński, G.
    Surma, M.
    Kossut, J.
    Yakovlev, D. R.
    Ossau, W.
    Landwehr, G.
    Kochereshko, V.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968448.pdf
    Data publikacji:
    1997-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    78.55.Et
    Opis:
    We report on growth and magnetooptical studies of two types of novel CdTe/CdMgTe quantum well structures having a precisely controlled grading of either the quantum well width or the donor concentration in a direction perpendicular to the growth axis. The presence of two-dimensional electron gas of varying concentration produced by the graded modulation doping was evidenced by observation of negatively charged exciton-electron complexes (X¯).
    Źródło:
    Acta Physica Polonica A; 1997, 92, 5; 1063-1066
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Indium Doping of CdTe Grown by Molecular Beam Epitaxy
    Autorzy:
    Karczewski, G.
    Zakrzewski, A.
    Kutrowski, M.
    Jaroszyński, J.
    Dobrowolski, W.
    Grodzicka, E.
    Janik, E.
    Wojtowicz, T.
    Kossut, J.
    Barcz, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1932089.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.55.Ln
    73.61.Ga
    Opis:
    We report on n-type indium doping of CdTe films grown by molecular beam epitaxy on (001) GaAs substrates. By adjusting the flux of In atoms we can precisely control the carrier concentration over three orders of magnitude - from 8 × 10$\text{}^{14}$ up to 1.3 × 10$\text{}^{18}$ cm$\text{}^{-3}$. In agreement with earlier reports we confirmed that Cd overpressure plays an important role in the doping process. The doping appears to be most effective for Cd/Te pressure ratio of 1.5. For this value of Cd/Te pressure ratio essentially 100% efficiency of doping is achieved at low In concentrations (< 10$\text{}^{18}$ cm$\text{}^{-3}$). At higher In concentrations acceptor impurities compensate shallow donors limiting the concentration of free carriers.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 241-244
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Physical Properties of ZnCoO Tetrapods and Nanofibers
    Autorzy:
    Gas, K.
    Fronc, K.
    Dziawa, P.
    Knoff, W.
    Wojciechowski, T.
    Zaleszczyk, W.
    Baranowska-Korczyc, A.
    Morhange, J.
    Paszkowicz, W.
    Elbaum, D.
    Karczewski, G.
    Wojtowicz, T.
    Szuszkiewicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1791329.pdf
    Data publikacji:
    2009-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Et
    78.67.Bf
    81.05.Dz
    81.07.Bc
    Opis:
    In this paper the physical properties of two types of Co-doped ZnO nanostructures: tetrapods and nanofibers grown by a rapid thermal evaporation process and prepared by the electrospinning technique, respectively, were investigated and analyzed. Surface morphology of the samples was examined using scanning electron microscopy. X-ray diffraction measurements showed hexagonal wurtzite crystal structure of both types of investigated nanostructures. Both X-ray diffraction and Raman scattering data confirmed high phase purity of the samples. The magnetic properties studied with the use of the SQUID magnetometer confirmed a presence of ferromagnetic order in analyzed nanostructures. The observed photoluminescence spectra exhibited two groups of lines. The first one, in the ultraviolet spectral range, is due to the optical transitions close to ZnO band gap, the second one in the red region is most probably related to the $Co^{2+}$ d-d internal transitions. The influence of native defects on the optical properties is also shown and discussed. All results reported here lead us to the conclusion that in the mixed crystal nanostructures obtained, a fraction of the $Zn^{2+}$ ions is substituted by $Co^{2+}$ ions.
    Źródło:
    Acta Physica Polonica A; 2009, 116, 5; 868-870
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Model Study of Inhomogeneous Line Broadening in Excitonic Spectra of Quantum Wells
    Autorzy:
    Astakhov, G. V.
    Kochereshko, V. P.
    Kosobukin, V. A.
    Yakovlev, D. R.
    Wojtowicz, T.
    Karczewski, G.
    Kossut, J.
    Ossau, W.
    Landwehr, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1969005.pdf
    Data publikacji:
    1998-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.20.Ci
    78.66.-w
    Opis:
    An approach is proposed to estimate separately parameters of homogeneous and inhomogeneous broadenings from an optical reflection line of a quasi-2D exciton. A phenomenological model is proposed to take into account statistically an inhomogeneous broadening of the exciton resonant spectra. The concept is applied to study a modulation-doped heterostructures with a single quantum well CdTe/CdMgTe. From exciton reflection lines taken in a magnetic field the temperature-dependent homogeneous and inhomogeneous broadening parameters as well as the exciton radiative decay rate are measured.
    Źródło:
    Acta Physica Polonica A; 1998, 94, 2; 235-239
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoluminescence Properties of ZnO and ZnCdO Nanowires
    Autorzy:
    Zaleszczyk, W.
    Fronc, K.
    Aleszkiewicz, M.
    Paszkowicz, W.
    Wróbel, J.
    Dłużewski, P.
    Kret, S.
    Klepka, M.
    Kłopotowski, Ł.
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047698.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Et
    78.67.Bf
    81.05.Dz
    81.07.Bc
    Opis:
    We report on the photoluminescence studies of ZnO and ZnCdO nanowires grown on SiO$\text{}_{2}$/Si substrates by low-pressure vapor phase synthesis. X-ray diffraction and transmission electron microscopy measurements show that the crystallographic structure of these ZnO and ZnCdO nanowires is of wurtzite-type with a high crystal perfection. Surface morphology of samples was determined by scanning electron microscopy and atomic force microscopy. The photoluminescence spectra of as-grown nanowires, nanowires extracted from the substrate and deposited onto Si wafer, and nanowires dispersed in ethanol by sonication were investigated at room temperature and compared to each other. The temperature dependence of the near band-gap photoluminescence emitted by the as-grown nanowires was also measured and analyzed.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 357-362
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Digital Magnetic Quantum Wells for the Study of Interface Sharpness of Molecular Beam Epitaxy Grown Structures
    Autorzy:
    Wojtowicz, T.
    Karczewski, G.
    Żakrzewski, A.
    Kutrowski, M.
    Janik, E.
    Dynowska, E.
    Kopalko, K.
    Kret, S.
    Kossut, J.
    Laval, J. Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/1931933.pdf
    Data publikacji:
    1995-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.20.Dx
    78.55.Et
    Opis:
    We report on the growth and basic characterization of digital magnetic quantum wells, that is, quantum wells in which the well material is itself a short period superlattice composed of alternating diluted magnetic and nonmagnetic semiconductor layers each only a few monolayers thick. These novel structures can be useful in a variety of studies, including studies of barrier-well interface sharpness.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 1; 165-168
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cubic MnTe - Growth by Molecular Beam Epitaxy and Basic Structural Characterization
    Autorzy:
    Zakrzewski, A.
    Janik, E.
    Dynowska, E.
    Leszczyński, M.
    Kutrowski, M.
    Wojtowicz, T.
    Karczewski, G.
    Bąk-Misiuk, J.
    Domagała, J.
    Kossut, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1873112.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.Pp
    68.55.Bd
    68.55.Jk
    Opis:
    We report on growth by molecular beam epitaxy of thick layers of MnTe with zinc blende structure. Films as thick as 5.6 µm were obtained. Characterization by X-ray diffraction proved their good structural quality. We determined the lattice constant and its temperature dependence. Broad luminescence due to internal Mn$\text{}^{2+}$- transitions was observed. It showed an unexpected temperature dependence.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 433-436
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Photoluminescence Properties of ZnO Nanowires Grown on Ni Substrate
    Autorzy:
    Zaleszczyk, W.
    Fronc, K.
    Przeździecka, E.
    Janik, E.
    Czapkiewicz, M.
    Wróbel, J.
    Paszkowicz, W.
    Kłopotowski, Ł.
    Karczewski, G.
    Wojtowicz, T.
    Presz, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812028.pdf
    Data publikacji:
    2008-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.55.Et
    78.67.Bf
    81.05.Dz
    81.07.Bc
    Opis:
    Photoluminescence studies of zinc oxide nanowires produced by a carbo-thermal method on a nickel foil substrate are reported. Two types of as-grown samples: the first - containing only buffer film, and the second - containing both zinc oxide nanowires and buffer film grown in the same technological process, were investigated by means of the temperature-dependent photoluminescence. X-ray diffraction measurements of buffer film show that it is polycrystalline and is composed from wurtzite-type ZnO (main phase) and includes minority phases: rock salt type (Ni,Zn)O and hexagonal C₃N₄. The shape of the apparently monocrystalline nanowires is characterized by hexagonal section matching with the expectations of the hexagonal ZnO structure. The presence of LO-phonon replicas in photoluminescence spectra for the second sample is used as an argument for confirmation that ZnO nanowires are single crystalline. The method of growth of ZnO nanowires on nickel oxide opens perspectives to produce $Zn_{1-x}Ni_{x}O$ diluted magnetic semiconductor nanowires.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 5; 1451-1456
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Raman Characterization of MBE-Grown Layered MnTe/CdTe Structures
    Autorzy:
    Szuszkiewicz, W.
    Jouanne, M.
    Morhange, J.
    Kanehisa, M. A.
    Mariette, H.
    Hartmann, J. M.
    Dynowska, E.
    Karczewski, G.
    Wojtowicz, T.
    Kossut, J.
    Barnaś, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968435.pdf
    Data publikacji:
    1997-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.30.Ds
    78.30.-j
    75.70.Ak
    Opis:
    Raman scattering measurements on (MnTe)$\text{}_{8}$/(Cd$\text{}_{0.64}$Zn$\text{}_{0.36}$Te)$\text{}_{8}$ multilayer grown by MBE method and on various (MnTe)$\text{}_{n}$/(CdTe)$\text{}_{12}$ multilayers (where n=8,12,16,24) were performed at low temperatures. In the z̅(x,x)z polarization, structures corresponding to folded acoustic phonons were found. In z̅(x,y)z polarization new complex structures were observed in the low-frequency part of Raman scattering spectra. A possible magnetic origin of these structures is discussed.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 5; 1021-1024
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Half-Parabolic Quantum Wells of Diluted Magnetic Semiconductor Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te
    Autorzy:
    Kutrowski, M.
    Wojtowicz, T.
    Cywiński, G.
    Karczewski, G.
    Janik, E.
    Dynowska, E.
    Kossut, J.
    Kossacki, P.
    Fiederling, R.
    Pfeuffer-Jeschke, A.
    Ossau, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968307.pdf
    Data publikacji:
    1997-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    75.50.Pp
    78.66.Hf
    Opis:
    We report on magnetooptical studies of MBE-grown half-parabolic CdTe/Cd$\text{}_{x}$Mn$\text{}_{1-x}$Te quantum well structures. The value of the valence band offset Q$\text{}_{v}$=0.4 ± 0.05 was determined by comparing energies of optical transitions in the absence of a magnetic field with model calculations. This value was verified by fitting the observed spin splitting of the lowest heavy hole (hh) state. We discuss also the temperature dependence of Q$\text{}_{v}$.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 5; 887-890
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nutritional status, morphological and biochemical blood parameters in HIV-positive adults from northern Poland
    Autorzy:
    Lebiedzinska, A.
    Majewski, M.
    Waszkiewicz, M.
    Maksymowicz-Jaroszuk, J.
    Grzeszczuk, A.
    Bierzynska, N.
    Lemanska, M.
    Jankowska, M.
    Smiatacz, T.
    Szefer, P.
    Karczewski, J.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/14855.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
    Źródło:
    Journal of Elementology; 2018, 23, 3
    1644-2296
    Pojawia się w:
    Journal of Elementology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electrical and Structural Properties of Ohmic Contacts to n-Type and High Resistivity CdTe
    Autorzy:
    Kamińska, E.
    Piotrowska, A.
    Guziewicz, M.
    Gierlotka, S.
    Papis, E.
    Łusakowski, J.
    Szadkowski, K.
    Kwiatkowski, S.
    Dietl, T.
    Grabecki, G.
    Jaroszyński, J.
    Karczewski, G.
    Zakrzewski, A. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1873052.pdf
    Data publikacji:
    1995-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    73.40.Ns
    Opis:
    The interaction between CdTe and In during the formation of an ohmic contact has been investigated. Emphasis is placed on the study of the effect of thermally induced sublimation of cadmium on electrical properties of contacts. Presented results prove the effectiveness of cap annealing and rapid thermal processing in fabrication of improved ohmic contacts with limited Cd losses during the contacting procedure.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 2; 411-414
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Growth and Properties of ZnMnTe Nanowires
    Autorzy:
    Zaleszczyk, W.
    Janik, E.
    Presz, A.
    Szuszkiewicz, W.
    Morhange, J. F.
    Dłużewski, P.
    Kret, S.
    Kirmse, H.
    Neumann, W.
    Dynowska, E.
    Domagała, J. Z.
    Caliebe, W.
    Aleszkiewicz, M.
    Pacuski, W.
    Golnik, A.
    Kossacki, P.
    Baczewski, L. T.
    Petroutchik, A.
    Karczewski, G.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047697.pdf
    Data publikacji:
    2007-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    61.46.Df
    68.65.La
    78.55.Et
    78.67.Bf
    81.15.Hi
    Opis:
    Catalytically enhanced growth of ZnMnTe diluted magnetic semiconductor nanowires by molecular beam epitaxy is reported. The growth is based on the vapor-liquid-solid mechanism and was performed on (001) and (011)-oriented GaAs substrates from elemental sources. X-ray diffractometry, scanning and transmission electron microscopy, atomic force microscopy, photoluminescence spectroscopy, and Raman scattering were performed to determine the structure of nanowires, their chemical composition, and morphology. These studies revealed that the obtained ZnMnTe nanowires possess zinc-blende structure, have an average diameter of about 30 nm, typical length between 1 and 2μm and that Mn$\text{}^{2+}$ ions were incorporated into substitutional sites of the ZnTe crystal lattice.
    Źródło:
    Acta Physica Polonica A; 2007, 112, 2; 351-356
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Morphology and Selected Properties of Core/Shell ZnTe-Based Nanowire Structures Containing ZnO
    Autorzy:
    Gas, K.
    Janik, E.
    Zaleszczyk, W.
    Pasternak, I.
    Dynowska, E.
    Fronc, K.
    Kolkovsky, V.
    Kret, S.
    Morhange, J. F.
    Reszka, A.
    Wiater, M.
    Caliebe, W.
    Karczewski, G.
    Kowalski, B. J.
    Szuszkiewicz, W.
    Wojtowicz, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047950.pdf
    Data publikacji:
    2011-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.37.Hk
    68.37.Lp
    68.65.La
    81.07.Vb
    Opis:
    We report on an approach to fabricate ZnTe-based core/shell radial heterostructures containing ZnO, as well as on some of their physical properties. The molecular beam epitaxy grown ZnTe nanowires constituted the core of the investigated structures and the ZnO shells were obtained by thermal oxidation of ZnTe NWs. The influence of the parameters characterizing the oxidation process on selected properties of core/shell NWs were examined. Scanning electron microscopy revealed changes of the NWs morphology for various conditions of the oxidation process. X-ray diffraction, high resolution transmission electron microscopy, and Raman scattering measurements were applied to reveal the presence of ZnTe single crystal core and polycrystalline ZnO-shell of investigated structure.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 5; 612-614
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-85 z 85

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