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Wyszukujesz frazę "Wojtowicz, A. J." wg kryterium: Autor


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:
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:
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:
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:
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:
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:
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:
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:
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:
Far-Infrared Magneto-Optical Studies of HgTe-CdTe Superlattices in the Semimetallic Regime
Autorzy:
Wojtowicz, T.
Dobrowolska, M.
Furdyna, J.K.
Meyer, J. R.
Bartoli, F. J.
Hoffman, C. A.
Ram-Mohan, L. R.
Powiązania:
https://bibliotekanauki.pl/articles/1888086.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.65.Fa
78.30.Fs
Opis:
We review recent magneto-optical investigations performed on HgTe-CdTe semimetallic superlattices. Far infrared magnetotransmission data obtained as a function of temperature, photon energy, and sense of circular polarization are compared with the predictions of a comprehensive new theory which fully incorporates the complexities of type-III superlattice band structure. It is found that the theory accounts for nearly all of the many unusual features which have been observed experimentally. These include the occurrence of two cyclotron resonances due to holes; the coexistence of electron and hole cyclotron resonances in the low temperature limit; the observation of three distinct CRA minima; a step-like change in the temperature dependence of the electron cyclotron mass; and a dramatic increase of the CRI absorption peak intensity with increasing magnetic field.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 245-254
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:
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:
Light-Induced Gratings in CdMnTeSe:In Crystals
Autorzy:
Koziarska-Glinka, B.
Ponder, M.
Wojtowicz, T.
Miotkowski, I.
Langer, J. M.
Suchocki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1968302.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.62.Dh
42.65.Hw
61.72.Ji
Opis:
We show that DX-like centers in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te$\text{}_{1-y}$Se$\text{}_{x}$:In crystal can be used in writing volume holographic gratings. The scattering efficiency is higher than 10% which proves the dispersive character of the light-induced gratings. Two different metastable centers with different lattice relaxation were found in the crystal. Measurements of the power dependence of the degenerate four-wave mixing scattering efficiency testify that both of these centers have negative U properties.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 883-886
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:
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

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