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Wyświetlanie 1-13 z 13
Tytuł:
Luminescence Decay Kinetics in GaN Studied by Frequency Domain Measurements
Autorzy:
Mickevičius, J.
Vitta, P.
Tamulaitis, G.
Žukauskas, A.
Shur, M.
Zhang, J.
Yang, J.
Gaska, R.
Powiązania:
https://bibliotekanauki.pl/articles/1813195.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
78.55.Cr
Opis:
Carrier dynamics in high-quality GaN epilayer was investigated at two extreme excitation levels. Carrier lifetime under high excitation conditions was estimated by using light-induced transient grating technique. Measurements at extremely low excitation power density were performed by using frequency-domain fluorescence lifetime technique. The study was performed in a wide temperature range from 8 to 300 K. The results revealed the influence of donor-acceptor pair recombination and carrier trapping processes.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 833-837
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Bistability Due to Photo-Induced Charge Transfer in a Type-II GaAs/AlAs Quantum Well
Autorzy:
Teissier, R.
Planel, R.
Mollot, F.
Powiązania:
https://bibliotekanauki.pl/articles/1921565.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
42.65.Pc
72.20.Jv
Opis:
We present a bistability of low temperature photoluminescence in a n-i-n type-II GaAs/AlAs quantum heterostructure. Spectral analysis and electrical measurements indicate that the two states correspond to hole accumulation in different layers. The transition occurs with the alignment of electronic Γ and X states due to optical pumping, and no external voltage bias is needed.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 656-659
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photovoltaic Effect with a Spectrally Dependent Sign in Type-II GaAlAs Heterostructure
Autorzy:
Jeżewski, M.
Teissier, R.
Mollot, F.
Planel, R.
Powiązania:
https://bibliotekanauki.pl/articles/1923840.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
72.40.+w
72.20.Jv
Opis:
An asymmetric n-i-n like-II GaAs/GaAlAs/AlAs quantum heterostructure was designed and fabricated in order to observe a static photovoltage with a spectrally dependent sign. This photovoltage is associated with a light induced spatial separation of electrons and holes within selected regions of the structure. The observed photovoltage spectrum is compared with luminescence and luminescence excitation results.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 833-836
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Electric Field on Recombination Dynamics of Quantum Confined Carriers
Autorzy:
Korona, K. P.
Borysiuk, J.
Skierbiszewski, C.
Porowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/2047384.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
72.20.Jv
78.55.Cr
Opis:
We present time-resolved photoluminescence measurements of GaN/AlGaN low dimensional structures showing very characteristic changes of dynamics related to strong electric field. Strong piezoelectric and spontaneous polarizations built-in in nitride structures lead to the changes in spatial separation of carriers which leads to changes in recombination energies and radiative lifetimes of the carriers. The observed effect can be well described by a simple exponential relation. The observed dependence can be explained by an approximated model of quantum-confined Stark effect based on the Airy functions.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 243-247
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-Resolved Transient Grating Spectroscopy for Studies of Nonequilibrium Carrier Dynamics in Wide Band-Gap Semiconductors
Autorzy:
Jarašiūnas, K.
Malinauskas, T.
Neimontas, K.
Gudelis, V.
Aleksiejūnas, R.
Powiązania:
https://bibliotekanauki.pl/articles/2046917.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
78.47.+p
78.55.Cr
Opis:
Using interdisciplinary fields relevant to a highly excited semiconductor - nonequilibrium phenomena in high density plasma, light-induced changes of optical properties, and dynamic holography, we developed time-resolved four-wave mixing technique for monitoring the spatial and temporal carrier dynamics in wide band-gap semiconductors. This opened a new possibility to analyse fast electronic processes in a non-destructive "all-optical" way, i.e. without any electrical contacts. This technique allowed evaluation of recombination and transport processes and the determination of important carrier parameters which directly reveal the material quality: carrier lifetime, bipolar diffusion coefficients, surface recombination rate, nonlinear recombination rate, diffusion length, threshold of stimulated recombination. The recent experimental studies of differently grown group III-nitrides (heterostructures and free standing films) as well silicon carbide epilayers by nondegenerate picosecond four-wave mixing are presented.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 201-209
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AlGaAs to GaAs Energy Transfer Mechanisms in AlGaAs/GaAs Structures
Autorzy:
Karpińska, K.
Godlewski, M.
Żytkiewicz, Z. R.
Chen, W. M.
Weber, E. R.
Powiązania:
https://bibliotekanauki.pl/articles/1921617.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
76.70.Hb
78.55.Cr
Opis:
The results of photoluminescence and optically detected cyclotron resonance experiments are presented for thick AlGaAs epilayers grown by liquid phase electroepitaxy method on GaAs:Cr substrate. These results indicate an efficient energy transfer from excited AlGaAs to GaAs.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 713-716
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transients of Carrier Recombination and Diffusion in Highly Excited GaN Studied by Photoluminescence and Four-Wave Mixing Techniques
Autorzy:
Juršėnas, S.
Miasojedovas, S.
Kurilčik, G.
Žukauskas, A.
Aleksiejūnas, R.
Malinauskas, T.
Sūdžius, M.
Jarašiūnas, K.
Powiązania:
https://bibliotekanauki.pl/articles/2041739.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
72.20.Jv
78.55.Cr
Opis:
Time-resolved photoluminescence and four-wave mixing techniques have been combined for studies of carrier relaxation dynamics in a highly photoexcited GaN epilayer. For a moderate excitation density below 1 mJ/cm$\text{}^{2}$, carrier recombination was due to free carrier capture by deep traps. The characteristic time of carrier capture,τ$\text{}_{e}$=550 ps, was measured under deep trap saturation regime. The ambipolar diffusion coefficient for free carriers, D=1.7 cm$\text{}^{2}$/s, was estimated from the analysis of the transients of the light-induced gratings of various periods. A complete saturation of the four-wave mixing efficiency was observed for the excitation energy density exceeding 1.5 mJ/cm$\text{}^{2}$. The latter saturation effect was shown to be related to electron-hole plasma degeneration, which results in a significant enhancement of carrier recombination rate due to onset of stimulated emission.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 240-244
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Optical Characterization of Carrier Lifetimes in GaN Layers by Time-Resolved Four-Wave Mixing and Photoluminescence Techniques
Autorzy:
Malinauskas, T.
Jarašiūnas, K.
Powiązania:
https://bibliotekanauki.pl/articles/2044502.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
78.47.+p
78.55.Cr
Opis:
We provide numerical analysis of nonequilibrium carrier dynamics in GaN layers at interband photoexcitation by a picosecond light pulse. By solving the continuity equation for bipolar carrier plasma, we analyze spatial and temporal evolution of carrier density. We show that fast carrier diffusion to the bulk determines the carrier in-depth profile in GaN epilayers with a thickness larger than the carrier diffusion length. By integrating the carrier spatial profiles at experimental conditions, corresponding to time-resolved four-wave mixing and time-resolved photoluminescense we simulate the four-wave mixing and time-resolved photoluminescense kinetics in subnanosecond time domain. The modeling data using parameters of the studied GaN epilayers (their thickness, diffusion coefficient, carrier lifetime, and absorption coefficients at emission wavelengths) were compared with the experimental results. The analysis provided conditions at which the discrepancy between the measured carrier lifetime by time-resolved photoluminescense and time-resolved four-wave mixing may occur. For hydride-vapor phase epitaxy GaN layers with a large diffusion length, the fast photoluminescense kinetics are confirmed by modeling and experiments that they are due to diffusion governed carrier in-depth redistribution, while four-wave mixing kinetics remain insensitive for carrier in-depth redistribution.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 781-787
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence of Highly Excited Nonpolar a-Plane GaN and AlGaN/GaN Multiple Quantum Wells
Autorzy:
Juršėnas, S.
Kuokštis, E.
Miasojedovas, S.
Kurilčik, G.
Žukauskas, A.
Chen, C. Q.
Yang, J. W.
Adivarahan, V.
Asif Khan, M.
Powiązania:
https://bibliotekanauki.pl/articles/2038100.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
73.21.Fg
72.20.Jv
78.47.+p
Opis:
Carrier recombination dynamics in polar and nonpolar GaN epilayers and GaN/AlGaN multiple quantum wells grown over sapphire substrates with various crystallographic orientation were studied under high photoexcitation by 20 ps laser pulses. The transient of luminescence featured a significant enhancement in nonradiative recombination of free carriers for nonpolar a-plane GaN epilayers compared to conventional c-plane samples. The epitaxial lateral overgrowth technique was demonstrated to significantly improve the quality of nonpolar a-plane films. This was proved by more than 40-fold increase in luminescence decay time (430 ps compared to ≤10 ps in the ordinary a-plane epilayer). Under high-excitation regime, a complete screening of built-in electric field by free carriers in multiple quantum wells grown on c-plane and r-plane sapphire substrates was achieved. Under such high excitation, luminescence efficiency and carrier lifetime of multiple quantum wells was shown to be determined by the substrate quality.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 567-573
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence of Highly Photoexcited GaN Epilayers and Heterostructures Grown on Different Sapphire Crystal Planes
Autorzy:
Juršėnas, S.
Miasojedovas, S.
Kurilčik, G.
Liuolia, V.
Žukauskas, A.
Chen, C. Q.
Yang, J. W.
Kuokštis, E.
Adivarahan, V.
Asif Khan, M.
Powiązania:
https://bibliotekanauki.pl/articles/2041736.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
73.21.Fg
72.20.Jv
78.47.+p
Opis:
GaN epilayers and AlGaN/GaN multiple quantum wells grown by metalorganic chemical vapor deposition on different crystal planes (c, a, and r) of the sapphire substrate were studied by excitation intensity dependent and time-resolved photoluminescence. In polar multiple quantum wells grown on a- and c-planes, a blueshift of the luminescence band with increasing the excitation energy was observed, indicating that screening of built-in field by free carriers takes place, whereas in nonpolar r-plane grown multiple quantum wells, the luminescence band maintained an almost constant peak position. Full screening of built-in field was achieved at the excitation densities higher than 0.3 mJ/cm$\text{}^{2}$. Under conditions of screened built-in electric field the structures were characterized by carrier lifetime. It was shown that nonpolar multiple quantum wells suffer from high density of nonradiative traps that can be due to substrate related threading dislocations.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 235-239
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optically Detected Magnetic Resonance Studies of Te-Related Shallow Donors in Al$\text{}_{x}$Ga$\text{}_{1-x}$As
Autorzy:
Godlewski, M.
Fronc, K.
Chen, W. M.
Monemar, B.
Powiązania:
https://bibliotekanauki.pl/articles/1890838.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
72.20.Jv
76.70.Hb
78.55.Cr
Opis:
The first studies of the Optically Detected Magnetic Resonance (ODMR) of Te-doped (x = 0.42) are presented. The ODMR data indicate an efficient energy transfer between epilayer and GaAs substrate.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 341-344
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stimulated Emission from the MBE Grown Homoepitaxial InGaN Based Multiple Quantum Wells Structures
Autorzy:
Ivanov, V.
Godlewski, M.
Miasojedovas, S.
Juršėnas, S.
Kazlauskas, K.
Žukauskas, A.
Skierbiszewski, C.
Siekacz, M.
Leszczyński, M.
Perlin, P.
Suski, T.
Grzegory, I.
Powiązania:
https://bibliotekanauki.pl/articles/1179597.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
73.21.Fg
72.20.Jv
78.47.+p
Opis:
We report on photoluminescence characterization of InGaN based laser structures grown by homoepitaxial radio frequency plasma-assisted molecular beam epitaxy. Owing to Si doped barriers, the structures show a negligible impact of the built-in electric field, which was proved by excitation intensity dependent and quantum well width dependent luminescence experiments. Relatively low variation in band potential due to inhomogeneous distribution of In was quantitatively estimated from the photoluminescence temperature behavior using Monte Carlo simulation of in-plane carrier hopping and optically detected cyclotron resonance experiments. Efficient stimulated emission with a low threshold for optically pumped laser structures was observed.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 225-229
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of Excitation Transfer Inside InAs/GaAs Quantum Dot System
Autorzy:
Korona, K. P.
Babiński, A.
Raymond, S.
Wasilewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2046919.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
72.20.Jv
78.67.Hc
78.55.Cr
Opis:
We present time-resolved photoluminescence investigations of InAs/GaAs structures containing quantum dots with the ground state at 1.43 eV. State filling effect and a Pauli blocking effect were clearly observed. These effects significantly influenced dynamics of excitation transfer from upper to lower state inside a dot leading to non-exponential dynamics. Numerical model based on nonlinear rate equations was proposed. The model described well the experimental data providing values of: lifetime of the ground state 0.53±0.03 ns, lifetime of excited state (when the ground state is full) 1.1±0.2 ns, and internal relaxation time (when the ground state is empty) 0.07±0.01 ns.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 219-224
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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