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208 results on '"Vorobjev, L. E."'

3. Monopolar Optical Orientation of Electronic Spins in Semiconductors

Author

Tarasenko, S. A., Ivchenko, E. L., Bel'kov, V. V., Ganichev, S. D., Schowalter, D., Schneider, Petra, Sollinger, M., Prettl, W., Ustinov, V. M., Zhukov, A. E., and Vorobjev, L. E.

Subjects
Condensed Matter
Abstract

It is shown that absorption of circularly polarized infrared radiation due to intraband (Drude-like) transitions in n-type bulk semiconductors and due to intra-subband or inter-subband transitions in quantum well (QW) structures results in a monopolar spin orientation of free electrons. Spin polarization in zinc-blende-structure based QWs is demonstrated by the observation of the spin-galvanic and the circular photogalvanic effects. The monopolar spin orientation in n-type materials is shown to be possible if an admixture of valence band states to the conduction band wave function and the spin-orbit splitting of the valence band are taken into account.

Published
2003

4. Optical Spin Orientation under Inter- and Intra-Subband Transitions in QWs

Author

Tarasenko, S. A., Ivchenko, E. L., Bel'kov, V. V., Ganichev, S. D., Schowalter, D., Schneider, Petra, Sollinger, M., Prettl, W., Ustinov, V. M., Zhukov, A. E., and Vorobjev, L. E.

Subjects
Condensed Matter
Abstract

It is shown that absorption of circularly polarized infrared radiation achieved by inter-subband and intra-subband (Drude-like) transitions results in a monopolar spin orientation of free carriers. The monopolar spin polarization in zinc-blende-based quantum wells (QWs) is demonstrated by the observation of the spin-galvanic and circular photogalvanic effects. It is shown that monopolar spin orientation in n-type QWs becomes possible if an admixture of valence band states to the conduction band wave function and the spin-orbit splitting of the valence band are taken into account.

Published
2003

5. Circular photogalvanic effect induced by monopolar spin orientation in p-GaAs/AlGaAs MQW

Author

Ganichev, S. D., Ivchenko, E. L., Ketterl, H., Vorobjev, L. E., and Prettl, W.

Subjects
Physics - Instrumentation and Detectors, Condensed Matter - Materials Science
Abstract

The circular photogalvanic effect (CPGE) has been observed in (100)-oriented $p$-GaAs/AlGaAs quantum wells at normal incidence of far-infrared radiation. It is shown that monopolar optical spin orientation of free carriers causes an electric current which reverses its direction upon changing from left to right circularly polarized radiation. CPGE at normal incidence and the occurence of the linear photogalvanic effect indicate a reduced point symmetry of studied multi-layered heterostructures. As proposed, CPGE can be utilized to investigate separately spin polarization of electrons and holes and the symmetry of quantum wells., Comment: 4 pages, 3 figures

Published
2000
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9. Selective terahertz emission due to electrically excited 2D plasmons in AlGaN/GaN heterostructure.

Author

Shalygin, V. A., Moldavskaya, M. D., Vinnichenko, M. Ya., Maremyanin, K. V., Artemyev, A. A., Panevin, V. Yu., Vorobjev, L. E., Firsov, D. A., Korotyeyev, V. V., Sakharov, A. V., Zavarin, E. E., Arteev, D. S., Lundin, W. V., Tsatsulnikov, A. F., Suihkonen, S., and Kauppinen, C.

Subjects
MAXWELL equations, SUBMILLIMETER waves, HOT carriers, ELECTRON temperature, ELECTRIC fields
Abstract

Terahertz radiation emission from an electrically excited AlGaN/GaN heterostructure with a surface metal grating was studied under conditions of two-dimensional (2D) electron heating by the lateral electric field. Intensive peaks related to nonequilibrium 2D plasmons were revealed in the terahertz emission spectra with up to 4 times selective amplification of the radiation emission in the vicinity of 2D plasmon resonance. This selective emission was shown to be frequency-controllable by the grating period. Exact spectral positions of the 2D plasmon resonances were preliminarily experimentally detected with the help of equilibrium transmission spectra measured at various temperatures. The resonance positions are in a satisfactory agreement with the results of theoretical simulation of the transmission spectra performed using a rigorous solution of Maxwell's equations. The effective temperature of hot 2D electrons was determined by means of I – V characteristics and their analysis using the power balance equation. It was shown that for a given electric field, the effective temperature of nonequilibrium 2D plasmons is close to the hot 2D electron temperature. The work may have applications in GaN-based electrically pumped emitters of terahertz radiation. [ABSTRACT FROM AUTHOR]

Published
2019
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10. Impurity-assisted terahertz photoluminescence in compensated quantum wells.

Author

Makhov, I. S., Panevin, V. Yu., Firsov, D. A., Vorobjev, L. E., and Klimko, G. V.

Subjects
QUANTUM wells, SUBMILLIMETER waves, PHOTOLUMINESCENCE, CHARGE carriers, ELECTROMAGNETIC spectrum, AUDITING standards
Abstract

The terahertz radiation in GaAs/AlGaAs quantum wells with different types of doping was experimentally studied under interband optical excitation of nonequilibrium charge carriers. The structures doped only with donors, and the structures with a high degree of compensation of donors by acceptors were studied. The spectra of terahertz radiation associated with charge carrier transitions with the participation of shallow impurity states were obtained and analyzed. It was shown that the compensation of donors by acceptors leads to a significant increase in the intensity of terahertz photoluminescence. The spectra of near-infrared photoluminescence with the participation of donor and acceptor states were also studied and analyzed. [ABSTRACT FROM AUTHOR]

Published
2019
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29. Interaction of surface plasmon polaritons in heavily doped GaN microstructures with terahertz radiation.

Author

Melentev, G. A., Shalygin, V. A., Vorobjev, L. E., Panevin, V. Yu., Firsov, D. A., Riuttanen, L., Suihkonen, S., Korotyeyev, V. V., Lyaschuk, Yu. M., Kochelap, V. A., and Poroshin, V. N.

Subjects
POLARITONS, SURFACE plasmons, GALLIUM nitride, SUBMILLIMETER waves, MICROSTRUCTURE
Abstract

We present the results of experimental and theoretical studies of the surface plasmon polariton excitations in heavily doped GaN epitaxial layers. Reflection and emission of radiation in the frequency range of 2–20 THz including the Reststrahlen band were investigated for samples with grating etched on the sample surface, as well as for samples with flat surface. The reflectivity spectrum for p-polarized radiation measured for the sample with the surface-relief grating demonstrates a set of resonances associated with excitations of different surface plasmon polariton modes. Spectral peculiarities due to the diffraction effect have been also revealed. The characteristic features of the reflectivity spectrum, namely, frequencies, amplitudes, and widths of the resonance dips, are well described theoretically by a modified technique of rigorous coupled-wave analysis of Maxwell equations. The emissivity spectra of the samples were measured under epilayer temperature modulation by pulsed electric field. The emissivity spectrum of the sample with surface-relief grating shows emission peaks in the frequency ranges corresponding to the decay of the surface plasmon polariton modes. Theoretical analysis based on the blackbody-like radiation theory well describes the main peculiarities of the observed THz emission. [ABSTRACT FROM AUTHOR]

Published
2016
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36. Terahertz Emission due to Radiative Decay of Hot 2D Plasmons in AlGaN/GaN Heterojunction

Author

Shalygin, V. A., primary, Arteev, D. S., additional, Lundin, W. V., additional, Korotyeyev, V. V., additional, Suihkonen, S., additional, Kauppinen, C., additional, Moldavskaya, M. D., additional, Vinnichenko, M. Ya., additional, Panevin, V. Yu., additional, Maremyanin, K. V., additional, Firsov, D. A., additional, Vorobjev, L. E., additional, Sakharov, A. V., additional, and Zavarin, E. E., additional

Published
2019
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38. Two-dimensional plasmons in a GaN/AlGaN heterojunction

Author

Vinnichenko, M Ya, primary, Shalygin, V A, additional, Moldavskaya, M D, additional, Artemyev, A A, additional, Melentev, G A, additional, Vorobjev, L E, additional, Firsov, D A, additional, Korotyeyev, V V, additional, Sakharov, A V, additional, Zavarin, E E, additional, Arteev, D S, additional, Lundin, W V, additional, Suihkonen, S, additional, and Kauppinen, C, additional

Published
2019
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39. Interaction of surface plasmon–phonon polaritons with terahertz radiation in heavily doped GaAs epilayers

Author

Shalygin, V A, primary, Moldavskaya, M D, additional, Panevin, V Yu, additional, Galimov, A I, additional, Melentev, G A, additional, Artemyev, A A, additional, Firsov, D A, additional, Vorobjev, L E, additional, Klimko, G V, additional, Usikova, A A, additional, Komissarova, T A, additional, Sedova, I V, additional, and Ivanov, S V, additional

Published
2019
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40. Growth and optical characterization of 7.5 μm quantum-cascade laser heterostructures grown by MBE

Author

Babichev, A V, primary, Gladyshev, A G, additional, Kolodeznyi, E S, additional, Kurochkin, A S, additional, Sokolovskii, G S, additional, Bougrov, V E, additional, Karachinsky, L Ya, additional, Novikov, I I, additional, Dudelev, V V, additional, Nevedomsky, V N, additional, Slipchenko, S O, additional, Lutetskiy, A V, additional, Sofronov, A N, additional, Firsov, D A, additional, Vorobjev, L E, additional, Pikhtin, N A, additional, and Egorov, A Yu, additional

Published
2018
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46. Absorption of Far-Infrared Radiation in Ge/Si Quantum Dots

Author

Sofronov, A. N., primary, Balagula, R. M., additional, Firsov, D. A., additional, Vorobjev, L. E., additional, Tonkikh, A. A., additional, Sarkisyan, H. A., additional, Hayrapetyan, D. B., additional, Petrosyan, L. S., additional, and Kazaryan, E. M., additional

Published
2018
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49. Optical characterization of mid-infrared range quantum-cascade laser structures grown by MBE

Author

Gusev, G A, primary, Sofronov, A N, additional, Firsov, D A, additional, Vorobjev, L E, additional, Babichev, A V, additional, Usikova, A A, additional, Il’inskaya, N D, additional, Zadiranov, Yu M, additional, Nevedomsky, V N, additional, Sokolovskii, G S, additional, Ustinov, V M, additional, Gladyshev, A G, additional, Karachinsky, L Ya, additional, Novikov, I I, additional, and Egorov, A Yu, additional

Published
2017
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50. Impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field.

Author

Shalygin, V. A., Vorobjev, L. E., Firsov, D. A., Panevin, V. Yu., Sofronov, A. N., Melentyev, G. A., Antonov, A. V., Gavrilenko, V. I., Andrianov, A. V., Zakharyin, A. O., Suihkonen, S., Törma, P. T., Ali, M., and Lipsanen, H.

Subjects
*GALLIUM nitride, *LUMINESCENCE, *ELECTRIC fields, *ELECTROLUMINESCENCE, *PHOTOCONDUCTIVITY
Abstract

We report on the observation and experimental studies of impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field. The terahertz electroluminescence is observed in a wide range of doping levels (at noncompensated donor density from 4.5×1016 to 3.4×1018 cm-3). Spectra of terahertz luminescence and photoconductivity are studied by means of Fourier transform spectrometry. Distinctive features of the spectra can be assigned to intracenter electron transitions between excited and ground states of silicon and oxygen donors and to hot electron transitions to the donor states. [ABSTRACT FROM AUTHOR]

Published
2009
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