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


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:
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:
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:
Scattering Dynamics of Excitons in ZnSe Based Semimagnetic Semiconductors
Autorzy:
Nguyen, The Khoi
Mac, W.
Gaj, J.A.
Powiązania:
https://bibliotekanauki.pl/articles/1921546.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
78.30.Fs
Opis:
Resonant Raman scattering was measured for (Zn,Fe)Se and (Zn,Cr)Se with the magnetic ion mole fraction below 0.02. LO phonons and intra-Fe$\text{}^{++}$ transitions were observed. Polarization measurements versus magnetic field allowed to obtain polarization lifetimes (polariton flight times) in the sub-picosecond range.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 634-636
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:
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:
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:
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:
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:
Control of Ferromagnetism in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Based Quantum Wells
Autorzy:
Bertolini, M.
Boukari, H.
Ferrand, D.
Cibert, J.
Tatarenko, S.
Gilles, B.
Maślana, W.
Gaj, J. A.
Kossacki, P.
Dietl, T.
Powiązania:
https://bibliotekanauki.pl/articles/2035587.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Hx
75.50.Dd
75.50.Pp
78.55.Et
Opis:
New structures aiming at controlling the ferromagnetic properties of diluted magnetic semiconductor quantum wells are presented. The carrier density is controlled by applying a voltage across a p-i-n diode. A new method, creating a 2D hole gas by adjusting the distance between the quantum well and surface, offers opportunities for a broader range of structures.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 603-608
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:
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
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:
Influence of an Electric Field on Fine Properties of III-V and II-VI Quantum Dots Systems
Autorzy:
Kowalik, K.
Krebs, O.
Kudelski, A.
Golnik, A.
Lemaître, A.
Senellart, P.
Karczewski, G.
Kossut, J.
Gaj, J.
Voisin, P.
Powiązania:
https://bibliotekanauki.pl/articles/2038219.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.70.Ej
Opis:
We investigate the influence of an electric field on the optical properties of single quantum dots. For sample made of III-V compounds micron-size electro-optical structures were produced in order to apply an electric field in the dot plane. For several individual dots lines significant variations of the anisotropic exchange splitting with the field were observed. On sample made of II-VI compounds we demonstrate the influence of electric field fluctuations on the luminescence of a single quantum dot.
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 177-184
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

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