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1

Dynamics of the Intraband Light Absorption in Selectively Doped GaAs/AlGaAs Quantum Wells

100%

Vorobjev L., Panevin V., Fedosov N., Firsov D., Shalygin V., Seilmeier A., Schmidt S., Zibik E., Towe E., Kapaev V.

Acta Physica Polonica A

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2005

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vol. 107

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issue 2

429-434

EN

Spectral and temperature dependences of equilibrium and non-equi-intersubband light absorption in the mid-infrared spectral range were studied in selectively doped asymmetrical tunnel-coupled GaAs/AlGaAs quantum wells. The temporal evolution of the absorption studied by means of a picosecond pump-probe technique was found to have a biexponential character. The fast decay times are determined by intersubband electron relaxation due to electron scattering by optical phonons and impurities. The presence of long decay times in transient mid-infrared absorption is probably connected with electron transitions from the states in barrier (X and L valleys as well as deep centers) to the states of the quantum well. Experimentally determined intersubband scattering times are compared with the calculated ones.

2

Terahertz Radiation Emission by Hot Electrons from AlGaN/GaN Heterostructure

100%

Shalygin V., Vorobjev L., Firsov D., Sofronov A., Melentyev G., Lundin W., Nikolaev A., Sakharov A., Tsatsulnikov A.

Acta Physica Polonica A

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2011

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vol. 119

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issue 2

241-243

EN

In the present paper we report on the observation and study of intense spontaneous THz emission from modulation-doped AlGaN/GaN heterostructure under conditions of heating of two-dimensional electron gas in lateral electric field. The experimental results are compared with the model of blackbody-like thermal emission of hot 2D electrons. Complementary transport measurements and theoretical simulation were carried out to determine the dependence of effective electron temperature on electric field. The role of non-equilibrium optical phonon accumulation is discussed.

3

Terahertz Luminescence and Absorption under Impurity Breakdown in Quantum Wells and Strained Semiconductor Layers

81%

Vorobjev L., Firsov D., Shalygin V., Panevin V., Sofronov A., Ustinov V., Zhukov A., Egorov A., Andrianov A., Zakhar'in A., Ganichev S., Danilov S., Kozlov D.

Acta Physica Polonica A

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2008

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vol. 113

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issue 3

925-928

EN

We present the results of THz luminescence investigations in structures with Si-doped quantum wells and Be-doped GaAsN layers under strong lateral electric field. The peculiar property of these structures is the presence of resonant impurity states which arise due to dimensional quantization in quantum wells and due to built-in strain in GaAsN epilayers. The experimentally obtained THz emission spectra consist of the lines attributed to intra-center electron transitions between resonant and localized impurity states and to the electron transitions involving the subband states. Absorption of THz radiation and its temperature dependence was also studied in structure with tunnel-coupled quantum wells at equilibrium conditions and under electric field.

4

Light Absorption and Photoluminescence in Quantum Dots and Artificial Molecules

72%

Firsov D., Vorobjev L., Panevin V., Fedosov N., Shalygin V., Samsonenko J., Tonkikh A., Cirlin G., Andreev A., Kryzhanovskaya N., Tarasov I., Pikhtin N., Ustinov V., Hanna S., Seilmeier A., Julien F., Zakharov N., Werner P.

Acta Physica Polonica A

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2005

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vol. 107

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issue 1

158-162

EN

Intraband absorption in n- and p-doped structures with InAs/GaAs quantum dots covered by InGaAs layers is studied both experimentally and theoretically. The absorption cross-section for p-type quantum dots was found to be significantly smaller than that for n-type quantum dots. Interband absorption bleaching under strong interband excitation is found and investigated in undoped quantum dot structures. Structures with artificial molecules were grown. Photoluminescence spectra and transmission electron microscopy images proves the presence of coupled symmetrical quantum dots.

Refine search results

Dynamics of the Intraband Light Absorption in Selectively Doped GaAs/AlGaAs Quantum Wells

Terahertz Radiation Emission by Hot Electrons from AlGaN/GaN Heterostructure

Terahertz Luminescence and Absorption under Impurity Breakdown in Quantum Wells and Strained Semiconductor Layers

Light Absorption and Photoluminescence in Quantum Dots and Artificial Molecules