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Wyszukujesz frazę "Gaj, A." wg kryterium: Autor


Tytuł:
Semimagnetic Semiconductors
Autorzy:
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2011142.pdf
Data publikacji:
1999-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.20.Ls
71.70.Gm
75.30.Et
Opis:
This paper contains a description and explanation of selected basic phenomena characteristic of bulk semimagnetic semiconductors: giant Faraday rotation and giant Zeeman splitting, mean field approximation and its limitations, ion-ion interaction, its measurements and its influence on magnetic properties, etc. The basic part is followed by a discussion of a personal choice of new perspectives open by the introduction of diluted magnetic semiconductors in semiconductor quantum structures. In particular, the role of magnetic ions in characterization of semiconductor quantum structures and low-dimensional excitonic systems is analyzed. Particular attention is paid to magnetooptical phenomena and magnetooptical experimental methods in large gap II-VI semimagnetic semiconductors.
Źródło:
Acta Physica Polonica A; 1999, 96, 5; 651-664
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Exciton Zeeman Splittings in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te from Faraday Rotation Measurements
Autorzy:
Stachow, A.
Nguyen, The Khoi
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/1933998.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
71.35.+z
Opis:
Reflectivity and Faraday rotation measurements were carried out on Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te bulk crystals in the complete zinc-blende range of composition 0 < x ≤ 0.71. From a comparison of the results of these two experiments for samples with x ≤ 0.3, we demonstrate that the Faraday angle Θ, measured in limited spectral range, is proportional to the energy splitting of exciton states ΔE, measured at the same temperature (2 K) and magnetic field B (up to 5 T). The determined proportionality constant was used to calculate ΔE values also for x > 0.3. This allowed us to find an empirical description of ΔE values for the whole range of compositions as a function of B and x.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 909-912
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of the Energy Gap in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se
Autorzy:
Gaj, J. A.
Nguyen, The Khoi
Arciszewska, M.
Lebecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/1891022.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
The energy gap and magnetic susceptibility of Cd$\text{}_{0.85}$Fe$\text{}_{0.15}$Se were measured in function of temperature. Experiments showed that the magnetic contribution to the variation of the energy gap in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se is not proportional to the product of magnetic susceptibility and temperature as it has been observed in Mn$\text{}^{++}$-containing semiconductors.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 405-407
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering Dynamics of Free Excitons on Fe$\text{}^{++}$ Ions in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se
Autorzy:
Gaj, J. A.
Nguyen, The Khoi
Nawrocki, M.
Golnik, A.
Lebecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/1891231.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
Inelastic scattering of excitons on Fe$\text{}^{++}$ ions in Cd$\text{}_{1-x}$Fe$\text{}_{x}$Se was studied by resonant Raman scattering. Polarization measurements were done using a modulation technique, allowing for the first time to determine the full polarization state of the detected light. The obtained results were compared to a simple calculation in an incoherent model of scattering on Fe$\text{}^{++}$ ions.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 409-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exchange Interaction in ZnCrSe Semimagnetic Semiconductor
Autorzy:
Mac, W.
Nguyen, The Khoi
Twardowski, A.
Gaj, J. A.
Demianiuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/1924249.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
Magnetoreflectance and magnetization of ZnCrSe were measured for B ≤ 5 T and T = 2 K. A linear dependence between exciton splitting and magnetization was found. The s, p-d exchange parameter was estimated: N$\text{}_{0}$α-N$\text{}_{0}$β=0.67eV.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 902-904
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Self-Assembled CdTe/ZnTe Quantum Dots
Autorzy:
Kowalik, K.
Kudelski, A.
Golnik, A.
Gaj, J. A.
Karczewski, G.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/2035754.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.70.Ej
Opis:
We present microluminescence investigations of self-assembled CdTe/ZnTe quantum dots. The dots proprieties resulting from our studies are: values of optical in-plane anisotropy parameters (electron - heavy hole exchange splitting and orientation of anisotropy) and value of effective Lande factor. Parameters giving information about in-plane anisotropy possess random distribution of values with the exchange splitting from 0 to 240 μeV. The effective Lande factor values for our dots are around g$\text{}^{*}$=-3.2 with a scatter of about 18%. Some PL lines exhibit sudden jumps of energetic position, related to variation of the charge state in their neighborhood.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 539-544
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetooptical Analysis of Interface Mixing in Pulsed Laser Evaporation and Epitaxy Grown CdTe/Cd$\text{}_{0.9}$Mn$\text{}_{0.1}$Te Multiple Quantum Well and Superlattice
Autorzy:
Lewalski, A.
Nguyen, The Khoi
Kossacki, P.
Gaj, J. A.
Dubowski, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/1929672.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
78.20.Ls
75.50.Pp
Opis:
A recently proposed magnetooptical method of determination of interface mixing was applied to CdTe/CdMnTe superstructures grown by pulsed laser evaporation and epitaxy. Diffusion length were found ≈ 5 Å for a multiple quantum well and > 15 Å for a superlattice. Ranges of Mn mole fractions and well width values enabling efficient application of the method were determined.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 571-574
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoluminescence of a CdTe Quantum Dot with a Single Manganese Ion in Voigt Configuration
Autorzy:
Koperski, M.
Goryca, M.
Kazimierczuk, T.
Kossacki, P.
Wojnar, P.
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2047960.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
75.75.-c
78.55.Et
78.67.Hc
Opis:
We present a study of the neutral exciton and negative trion recombination spectra of an individual CdTe quantum dot with a single manganese ion, in magnetic field measured in the Voigt configuration. We describe experimental results and compare with a theoretical model. The quantitative agreement between the model and the experiment allows us to determine separately the electron g-factor.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 618-620
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excitonic Giant Zeeman Effect in Wide Gap Diluted Magnetic Semiconductors Based on ZnO and GaN
Autorzy:
Pacuski, W.
Ferrand, D.
Kossacki, P.
Marcet, S.
Cibert, J.
Gaj, J. A.
Golnik, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046983.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.Hx
78.20.Ls
71.35.Ji
Opis:
We present a theoretical description of the excitonic giant Zeeman effect observed in wide gap diluted magnetic semiconductors (Zn,Co)O and (Ga,Mn)N. In these materials, A and B excitons present quite complex energy shifts and change of oscillator strengths under magnetic field. These features can be well reproduced using an excitonic Hamiltonian, taking into account ion-carrier exchange, wurtzite trigonal crystal field, spin-orbit and electron-hole exchange interactions.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 303-309
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Faraday Rotation and Photoionization of ZnCrSe Semimagnetic Semiconductor
Autorzy:
Mac, W.
Nguyen, The Khoi
Gaj, J. A.
Twardowski, A.
Demianiuk, M.
Stachow-Uciakowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1929663.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
Opis:
The magnetoabsorption and the Faraday rotation of ZnCrSe were measured for B ≤ 5 T and T = 2 K in the region of photon energies lower than the fundamental absorption edge. The circular dichroism of the photoionization absorption bane was observed and analyzed. The Faraday rotation was interpreted as due to the sum of contributions from interband and photoionization optical transitions.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 567-570
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long Decays of Excitonic Photoluminescence from CdTe/ZnTe Individual Quantum Dots
Autorzy:
Piechal, B.
Suffczyński, J.
Trajnerowicz, A.
Goryca, M.
Kossacki, P.
Golnik, A.
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2044525.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.67.Hc
78.55.Et
Opis:
We present time-resolved micro-photoluminescence study of self-assembled CdTe/ZnTe quantum dots. In addition to the fast radiative decay of the exciton, we observe long components, being of the order of a few nanoseconds. We observe that long decays are present for neutral exciton lines as well as on the biexciton ones. The temperature dependent measurements reveal the non-monotonic behaviour. We find also that the long decays are not mono-exponential. We conclude that the dark exciton states cannot be treated as the only source of long decays in the luminescence. We propose other possible explanation, which is the slowing of luminescence by carrier trapping in high energy states in quantum dots and barriers.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 831-836
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inter-Dot Coupling in a Self-Assembled Quantum Dot System
Autorzy:
Kazimierczuk, T.
Nowak, S.
Suffczyński, J.
Wojnar, P.
Golnik, A.
Gaj, J. A.
Kossacki, P.
Powiązania:
https://bibliotekanauki.pl/articles/2047689.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Et
Opis:
We present studies of resonant excitation of self-assembled CdTe/ZnTe quantum dots. Photoluminescence excitation measurements revealed existence of sharp resonances, common for photoluminescence lines attributed to different quantum dot charge states. We conclude from the ensemble of photoluminescence and photoluminescence excitation results that we observe energy transfer in coupled quantum dot pairs.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 321-324
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Femtosecond Dynamics of Neutral and Charged Exciton Absorption in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Quantum Well
Autorzy:
Płochocka, P.
Kossacki, P.
Maślana, W.
Radzewicz, C.
Gaj, J. A.
Cibert, J.
Tatarenko, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035611.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.40.Fy
78.47.+p
78.67.De
Opis:
We present a study of time-dependent transmission spectra of a modulation-doped Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te/Cd$\text{}_{1-y-z}$Zn$\text{}_{y}$Mg$\text{}_{z}$Te quantum well with variable hole gas concentration. We study the influence of pump pulses on excitonic absorption in subpicosecond time scale. A spectrally broad probe pulse of duration of 40 femtoseconds was used to record the absorption spectra at controlled delay. Studies of temporal evolution of exciton energies revealed coherence decay of linearly polarized excitons and thermalization of non-equilibrium exciton states. We found that a characteristic timescale for thermalization of non-equilibrium populations of photocreated excitons is between 0.8 and 3.6 ps. The timescale of this process depends on the hole concentration in quantum well: for higher hole concentration the decay is faster. Long-lived photo-induced magnetization accompanied by heating of the magnetic system was also observed.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 679-686
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Many-Body Interactions in the CdTe-Based Quantum Well under Strong Optical Excitation
Autorzy:
Płochocka, P.
Kossacki, P.
Piechal, B.
Maślana, W.
Golnik, A.
Cibert, J.
Tatarenko, S.
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2038365.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.De
71.35.Pq
78.47.+p
Opis:
We performed pump-probe time-resolved absorption measurements on a modulation p-doped (Cd,Mn)Te quantum well. The density of the 2D hole gas was controlled, in the 10$\text{}^{10}$ cm$\text{}^{-2}$ range, by additional cw illumination. Interactions between photocreated neutral (X) and charged (X$\text{}^{+}$) excitons and the 2D hole gas were analyzed. We found that the strongest effect is the influence of the carriers on both X and X$\text{}^{+}$ optical resonances. Neutral and charged excitons are screened by holes, which results in the decrease in their intensities. We conclude from polarization resolved experiments that this screening is spin-dependent: it is more efficient between holes with opposite spins. Binding holes into the charged excitons reduces the screening of the neutral excitons and leads to an enhancement of the neutral exciton intensity. We also analyzed weaker effects, due to exciton-exciton interaction, at a constant hole density. We found that the reduction of the neutral exciton intensity due to two different mechanisms (phase-space filling and biexciton formation) is almost equal. We observed a spin-dependent blue shift of the neutral exciton line in the presence of a population of neutral excitons created by the pump pulse. Due to the attractive interaction between excitons with opposite spins, the corresponding shift of the neutral exciton is smaller than that observed due to the interaction between excitons with the same spins.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 413-422
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of Very Small Zeeman Splittings in GaN:Mn,Mg by Faraday Rotation
Autorzy:
Wołoś, A.
Kossacki, P.
Golnik, A.
Kamińska, M.
Gaj, J. A.
Twardowski, A.
Grzegory, I.
Boćkowski, M.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035615.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
71.70.Ej
71.55.Eq
71.20.Nr
Opis:
In this work we demonstrate an application of Faraday rotation for measuring an extremely small Zeeman splitting of an Mn related absorption line placed at 1.417 eV in optical absorption spectrum of Mn and Mg doped gallium nitride. Analysis of the collected spectra allowed us to determine the value of the splitting as equal to 0.12±0.01 meV at 6 T. This data should help in establishing the nature of the observed absorption band.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 695-699
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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