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1. V. V. Belykh and M. V. Kochiev
   Heating by exciton and biexciton recombination in GaAs/AlGaAs quantum wells Phys. Rev. B, vol. 92, pp. 045307, (2015)
   аннотация

   
   Acomprehensive experimental investigation of exciton and biexciton recombination in GaAs/AlGaAs quantum wells is presented. Exciton and biexciton recombination times are found to be 16 and 55 ps, respectively.Amethod of determining the dynamics of the exciton temperature is developed. It is shown that both exciton and biexciton recombination processes increase the exciton temperature by an amount as high as ∼10 K. These processes impose a new restriction on the possibility of exciton Bose-Einstein condensation and make impossible its achievement in a system of direct excitons in GaAs quantum wells even for resonantly excited exciton gas. 10.1103/PhysRevB.92.045307
   

1. V. V. Belykh, D. A. Mylnikov and N. N. Sibeldin
   Dynamics of the transition from weak to strong exciton-photon coupling regime in a GaAs microcavity: angle resolved measurements Physica Status Solidi С, vol. 9, N5, p. 1230, (2012)
   аннотация

   
   The emission dynamics of a GaAs microcavity with embedded quantum wells at different angles of observation with respect to the sample normal under conditions of nonresonant picosecond-pulse excitation is studied. At considerably high excitation densities, above a certain threshold, a very intense, fast, and spectrally narrow (at small angles of observation) component in the PL dynamics appears at short times, with the spectral position corresponding to the bare cavity mode, indicating the onset of lasing in the weak coupling regime. At longer times lasing ceases and the transition from weak to strong coupling regime is observed, as it follows from the spectral positions of the peaks in time-resolved spectra at different angles of observation. At moderate excitation densities, kinetic dependences of the spectral shift and width of the lower polariton emission line (these parameters are often used to distinguish between strong and weak coupling regimes) as a function of angle of observation (polariton energy) are analyzed. In particular, it is shown that the decay time of the spectral shift is almost independent of the polariton energy and could be used as the characteristic time of the transition from weak to strong coupling regime. On the other hand, the decay time of the emission line broadening strongly depends on the polariton energy, indicating that the linewidth kinetics is essentially determined by the cooling of the electron-hole system. 10.1002/pssc.201100199
   
2. A. F. Adiyatullin, V. V. Belykh, V. I. Kozlovsky, V. S. Krivobok, V. P. Martovitsky, S. N. Nikolaev
   Влияние размытия гетерограницы на свойства экситонных состояний в квантовых ямах Zn(Cd)Se/ZnMgSSe ЖЭТФ, vol. 142, p. 1005, (2012)
   аннотация

   
   Exciton states in Zn(Cd)Se/ZnMgSSe quantum wells with different diffusion spreading of interfaces are studied by optical spectroscopy methods. It is shown that the emission spectrum of quantum wells at low temperatures is determined by free excitons and bound excitons on neutral donors. The nonlinear dependence of the stationary photoluminescence intensity on the excitation power density and the biexponential luminescence decay are explained by the neutralization of charged defects upon photoexcitation of heterostructures. With the stationary illumination on, durable (about 40 min) reversible changes in the reflection coefficient near the exciton resonances of quantum wells are observed. It is shown that, along with the shift of exciton levels, the spreading of heteroboundaries leads to three effects: an increase in the excitonphonon interaction, an increase in the energy shift between the emission lines of free and bound excitons, and a decrease in the decay time of exciton luminescence in a broad temperature range. The main reasons for these effects are discussed. 10.1134/S1063776112090014
   
3. J. Szeszko, V. V. Belykh, P. Gallo, A. Rudra, K. F. Karlsson, N. N. Sibeldin and E. Kapon
   Exciton confinement and trapping dynamics in double-graded-bandgap quantum nanowires Applied Physics Letters, vol. 100, p. 211907, (2012)
   аннотация

   
   We fabricate and study quantum dot structures incorporating quasi-one-dimensional excited states. The structures are realized by graded bandgap GaAs/AlGaAs quantum wires self-formed inside inverted tetrahedral pyramids. The ground state transitions exhibit typical characteristics of fully confined excitons, including single photon emission. Efficient carrier thermalization and relaxation, as well as correlated photon emission is observed also among the excited states, indicating the formation of quasi-one-dimensional multi-exciton states. These structures offer interesting possibilities for collecting and directing charge carriers towards heterostructured potential traps. 10.1063/1.4721660
   

1. V. V. Belykh, V. A. Tsvetkov, M. L. Skorikov and N. N. Sibeldin
   Nonlinear emission dynamics of a GaAs microcavity with embedded quantum wells Journal of Physics-Condensed Matter, vol. 23, p. 215302, (2011)
   аннотация

   
   The emission dynamics of a GaAs microcavity at different angles of observation with respect to the sample normal under conditions of nonresonant picosecond-pulse excitation is measured. At sufficiently high excitation densities, the decay time of the lower polariton emission increases with the polariton wavevector; at low excitation densities the decay time is independent of the wavevector. The effect of additional nonresonant continuous illumination on the emission originating from the bottom of the lower polariton branch is investigated. The additional illumination leads to a substantial increase in the emission intensity (considerably larger than the intensity of the photoluminescence excited by this illumination alone). This fact is explained in terms of acceleration of the polariton relaxation to the radiative states due to scattering by charge carriers created by the additional illumination. The results obtained show that, at large negative detunings between the photon and exciton modes, polariton–polariton and polariton–free carrier scattering are the main processes responsible for the filling of states near the bottom of the lower polariton branch. 10.1088/0953-8984/23/21/215302
   

1. В. В. Белых, М. Х. Нгуен, Н. Н. Сибельдин, М. Л. Скориков, В. А. Цветков, А. В. Шарков
   Динамика перехода от режима слабой связи к режиму сильной связи в системе экситонных поляритонов в полупроводниковых микрорезонаторах ЖЭТФ, т. 136, стр. 550, (2009)
   аннотация

   
   The dynamics of polaritonic emission of a GaAs-based microcavity with embedded quantum wells under nonresonant optical excitation is studied. Kinetic dependences of the intensity, spectral position, and linewidth of spontaneous and stimulated emission of the microcavity are measured. It is established that the dynamics of the high-frequency shift of the emission line is qualitatively similar to the dynamics of the emission intensity, but the spectral shift attains its maximum value before the peak intensity is reached. The emission linewidth is maximal immediately after the excitation pulse. Under the conditions of spontaneous emission, the linewidth decreases steadily with time, approaching the value corresponding to low polariton densities. Under lasing conditions, the linewidth is at a minimum when the stimulated-emission intensity attains its peak value. The experimental data are analyzed on the basis of a theoretical model that describes relaxation processes taking into account exciton-exciton and exciton-free carrier interactions. 10.1134/S1063776109090131
   
2. В. В. Белых, М. Х. Нгуен, Н. Н. Сибельдин, М. Л. Скориков, В. А. Цветков, А. В. Шарков
   Динамика излучения GaAs микрорезонатора с встроенными квантовыми ямами при высоких плотностях нерезонансного возбуждения Письма в ЖЭТФ, т. 89, стр. 681, (2009)
   аннотация

   
   In a GaAs-based microcavity with embedded quantum wells, the dynamics of emission processes under high levels of nonresonant picosecond laser-pulse excitation is studied. For pump levels above the stimulation threshold, the kinetics of the intensity, spectral position, and linewidth of the emission are measured. Upon the arrival of an excitation pulse, the emission line shifts to higher energies over a time interval comparable to the time it takes for the emission intensity to attain its peak value, and then shifts in the opposite direction towards its position at low polariton densities. The width of the emission line is largest immediately after the excitation pulse and attains a minimum when the stimulated-emission intensity is maximum. It is shown that after the excitation pulse, the system is initially in a weak exciton-photon coupling regime, and a transition to a strong-coupling regime occurs with time. 10.1134/S0021364009110113
   

1. В. В. Белых
   Влияние слабого магнитного поля на поляритон-электронное рассеяние в полупроводниковых микрорезонаторах ЖЭТФ, т. 131, стр. 932, (2007)
   аннотация

   
   The polarition linewidth is calculated as a function of magnetic field applied perpendicular to the microcavity plane for microcavity excition-polaritons scattered by free electrons in a quantum well. The calculated function exhibits oscillatory behavior; i.e., the scattering rate either increases or decreases with magnetic induction. Possible applications of this effect are discussed. 10.1134/S1063776107050159