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Wyszukujesz frazę "Karczewski, M." wg kryterium: Autor


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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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

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