共查询到20条相似文献,搜索用时 15 毫秒
1.
L. E. Vorob’ev V. L. Zerova D. A. Firsov G. Belenky L. Shterengas G. Kipshidze T. Hosoda S. Suchalkin M. Kisin 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(1):69-71
The dynamics of interband luminescence in structures with InGaAsSb-based quantum wells and barriers of different types was
studied at different temperatures and excitation levels. The lifetime of optically injected charge carriers in quantum wells
at different temperatures and optical excitation levels was determined. An increased recombination rate in structures with
deep electron quantum wells was discovered; it is associated with the occurrence of resonance Auger recombination. It was
concluded that the application of quinary solid solutions as barriers in laser structures for a 3—4 fum wavelength range is
to be preferred. 相似文献
2.
L. E. Vorob’ev 《JETP Letters》1998,68(5):417-425
A mechanism is proposed for obtaining intraband population inversion of electrons in size-quantization levels through the
injection of electron-hole pairs into the i region of a heterostructure with quantum wells or quantum dots. Key elements of the mechanism are the simultaneous generation
of interband (hv≈E
g
) near-IR radiation and the presence of a “metastable” level. In quantum wells such a level can be produced by making use
of the weak overlap of the wave functions of electrons in the levels of a quantum well of complicated configuration and exploiting
the characteristic features of the interaction of electrons with optical phonons in polar semiconductors. In quantum dots
such a level forms as a result of the phonon bottleneck effect. Estimates are made of the gain for mid-IR radiation in intraband
optical transitions of electrons.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 5, 392–399 (10 September 1998) 相似文献
3.
Collective intraband charge-density excitations in the quasi-two-dimensional electron system of double GaAs/AlGaAs quantum wells in an external parallel magnetic field B∥ are studied by inelastic light scattering. It has been found that the energy of the excitations under study (acoustic and optical plasmons) exhibits anisotropy depending on the mutual orientation of B∥ and the excitation quasi-momentum k. It is shown theoretically that, in a strong parallel magnetic field, the effects associated with the finite width of the quantum wells dominate over the effects associated with interlayer tunneling and determine the anisotropy of plasmons. The experimental data are compared with a theoretical calculation. 相似文献
4.
A. V. Larionov V. B. Timofeev J. Hvam K. Soerensen 《Journal of Experimental and Theoretical Physics》2000,90(6):1093-1104
Luminescence spectra of interwell excitons in GaAs/AlGaAs double quantum wells with electric-field-tilted bands (n-i-n) structures were studied. In these structures the electron and the hole in the interwell exciton are spatially separated between neighboring quantum wells by a narrow AlAs barrier. Under resonant excitation by circularly polarized light the luminescence line of the interwell excitons exhibited appreciable narrowing as their concentration increased and the degree of circular polarization of the photoluminescence increased substantially. Under resonant excitation by linearly polarized light the alignment of the interwell excitons increased as a threshold process with increasing optical pumping. By analyzing time-resolved spectra and the kinetics of the photoluminescence intensity under pulsed excitation it was established that under these conditions the rate of radiative recombination increases substantially. The observed effect occurs at below-critical temperatures and is interpreted in terms of the collective behavior of the interwell excitons. Studies of the luminescence spectra in a magnetic field showed that the collective exciton phase is dielectric and in this phase the interwell excitons retain their individual properties. 相似文献
5.
DeGui Kong GuangHong Ao YaChen Gao Qing Chang WenZhi Wu LingLing Ran Hong'An Ye 《Physica B: Condensed Matter》2012,407(21):4251-4253
Using the Z-scan technique and pump–probe technique with 130 fs laser pulses at 800 nm, we verify that an intraband one-photon absorption follows the interband two photon absorption. Particularly, we find that there is an intraband relaxation interspersed between these two absorption processes for some of the conduction band electrons but not all of them. In this study, we measure the interband two photon absorption coefficient and the absorptive cross sections associated with both excitation pathways within the conduction band. In addition, we estimate the time for relaxation of electrons within the conduction band to be 250 fs. 相似文献
6.
The electronic states of a hydrogenic donor in two-dimensional quantum rings are calculated by taking into account the finite width of the potential well in the ring. In addition, a strong magnetic field is applied perpendicular to the quantum ring. Using the effective-mass approximation at the Γ valley, the radial Hamiltonian for the envelope-function is exactly diagonalized in the case of on-center donors. The corresponding energy levels for different angular momenta are studied as a function of the applied magnetic field. In the case of off-center donors, a perturbation approach is considered and its limitations are discussed. Finally, we calculate the absorption spectra and oscillator strength for different intraband transitions, specifically for on-center donors. 相似文献
7.
E. C. Niculescu N. Eseanu 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,79(3):313-319
The exciton effects on the interband absorption spectra in near-surface square and
semiparabolic quantum wells under intense laser field are studied taking into account the correct
dressing effect for the confinement potential and electrostatic self-energy due to the repulsive
interaction between carriers and their image charges. We found that for near-surface quantum wells with
different shapes the laser field induces significant effects on their electronic and optical properties.
The numerical results for the InGaAs/GaAs system show that the red-shift of the absorption peak induced
by the increasing cap layer can be effectively compensated using the blue-shift caused by the enhanced
laser parameter. In square quantum well without laser field our theoretical values for the absorption
peak position are in good agreement with the available experimental data. As a key result, we conclude
that the optical properties in near-surface quantum wells can be tuned by tailoring the heterostructure
parameters: well shape, capped layer thickness and/or dielectric mismatch as well as the external field
radiation strength. 相似文献
8.
O. A. Shegai A. Yu. Berezovsky A. I. Nikiforov V. V. Ul’yanov 《Physics of the Solid State》2005,47(1):30-33
A nonmonotonic dependence of the lateral photoconductivity (PC) on the interband light intensity is observed in Si/Ge/Si and Si/Ge/SiOx structures with self-organized germanium quantum dots (QDs): in addition to a stepped increase in PC, a stepped decrease in PC is also observed. The effect of temperature and drive field on these features of the PC for both types of structures with a maximum nominal thickness of the Ge layer (NGe) is studied. The results obtained are discussed in the context of percolation theory for nonequilibrium carriers localized in different regions of the structure: electrons in the silicon matrix and holes in QDs. 相似文献
9.
D. A. Firsov L. E. Vorobjev V. A. Shalygin V. Yu. Panevin A. N. Sofronov S. D. Ganichev S. N. Danilov A. V. Andrianov A. O. Zakhar’in A. E. Zhukov V. S. Mikhrin A. P. Vasil’ev 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(2):246-248
Spontaneous emission of terahertz radiation from structures with GaAs/AlGaAs quantum wells in a longitudinal magnetic field has been studied. It is shown that some bands in the emission spectrum can be related to radiative electron transitions between resonant and localized impurity states, as well as to the transitions with participation of subband states. The temperature dependence of the equilibrium intraband absorption of terahertz radiation and its modulation in a longitudinal electric field in GaAs/AlGaAs quantum wells has been investigated. 相似文献
10.
I. M. Catalano A. Cingolani M. Lepore R. Cingolani K. Ploog 《Il Nuovo Cimento D》1990,12(10):1465-1474
Summary The two-photon absorption spectra of GaAs/AlGaAs multiple quantum well and superlattice structures have been experimentally
investigated by means of the nonlinear luminescence technique in different polarization configurations. A strong excitonic
effect overlapping the interband two-photon spectrum has been found and the selection rules for the excitonic transitions
have shown to greatly change for different polarizations. The comparison of linear and nonlinear absorption measurements provides
important information on the excited states of excitons in multiple quantum wells.
Work partially supported by M.P.I. 相似文献
11.
段坤杰 《原子与分子物理学报》2017,34(6)
在有效质量近似下,详细研究了直接带隙Ge/GeSi耦合双量子阱中带间光跃迁吸收系数和阈值能量随量子阱结构参数的变化情况。结果表明:随着量子阱阱宽增大,带间光跃迁吸收强度会逐渐减弱,阈值能量减小,吸收曲线向低能方向移动,出现了红移现象。增强耦合量子阱间的耦合效应使得带间光吸收强度显著提升。此外,与非对称耦合量子阱相比,耦合效应对对称耦合量子阱中光吸收系数的影响更为显著。 相似文献
12.
在有效质量近似下,详细研究了直接带隙Ge/Ge Si耦合双量子阱中带间光跃迁吸收系数和阈值能量随量子阱结构参数的变化情况.结果表明:随着量子阱阱宽增大,带间光跃迁吸收强度会逐渐减弱,阈值能量减小,吸收曲线向低能方向移动,出现了红移现象.增强耦合量子阱间的耦合效应使得带间光吸收强度显著提升.此外,与非对称耦合量子阱相比,耦合效应对对称耦合量子阱中光吸收系数的影响更为显著. 相似文献
13.
Radiative transitions associated with intraband electron tunneling through DC biased quantum well structures are analyzed theoretically. Spontaneous emission and stimulated emission of photons within the quantum well structure are calculated and estimates are made of the radiative transition rate in comparison with the damping loss. The absence of an inherent long wavelength emission cutoff is in contrast with interband transition devices and suggests applications of intraband transition devices as far infrared or microwave sources. 相似文献
14.
We have developed a theory of a transient intraband light absorption by semiconductor quantum dots. This absorption plays
an important role in the two-pulse pump-probe method, which enables determining the energy relaxation rates of electron-hole
excited states. We have considered all possible schemes of this process wherein the carrier frequency of optical pump pulses
is close to the resonance with the interband transition of the quantum-dot electronic subsystem, while the carrier frequency
of probe pulses is resonant to the intraband transition. For ensembles of identical and size-distributed quantum dots, the
probe pulse energy absorption induced by the pump pulse is analyzed in relation to the delay time between the pulses. We have
found that, under certain conditions, this dependence can be described by a single, two, or three exponentials. The exponents
of the exponentials are proportional to the energy relaxation rates of electron-hole excited states. 相似文献
15.
The energy spectrum of light-hole and heavy-hole excitons and optical absorption in a quantum well have been analyzed taking into account Rashba spin-orbit coupling. Interband and intraband exciton transitions have been considered. It has been shown that, in the presence of spin-orbit coupling, the probabilities of the interband and intraband photoelectric effects diverge in the vicinity of the threshold if the electron-hole interaction is neglected. The threshold probabilities of the interband and intraband photoelectric effects become finite when Coulomb interaction is taken into account. 相似文献
16.
A. A. Greshnov Yu. B. Vasil’ev N. N. Mikhailov G. Yu. Vasil’eva D. Smirnov 《JETP Letters》2013,97(2):102-106
Cyclotron-resonance measurements in 21-nm-thick HgTe/CdHgTe quantum wells of different crystallographic orientations have been performed. It has been found that, in contrast to the structures with the (001) orientation of the quantum-well plane, (013)-oriented quantum wells are semimetallic and their absorption spectra exhibit both electron and hole cyclotron-resonance lines. The simultaneous presence of the two types of charge carriers originates from an overlap between the upper heavy-hole quantum-confinement subbands hh1 and hh2. This overlap is caused by the strong interaction of these subbands with the Dyakonov-Khaetskii interface state. Calculations carried out using the eight-band kp-Hamiltonian indicate that, for known values of the band-structure parameters, the overlap between hh2 and hh1 subbands does not occur; this result is in agreement with the cyclotron-resonance data for (001)-oriented structures. The enhanced interaction between heavy-hole and interface states owing to the existence of steps at low-symmetry heterointerfaces may be the mechanism responsible for the appearance of an overlap between subbands in HgTe quantum wells with orientation different from (001). 相似文献
17.
Optical absorption spectra of polarized infrared radiation in p-type SiGe quantum-well structures have been investigated. Three types of structures with different magnitudes and signs of biaxial elastic strains have been studied. The light absorption factor has been found to double in the region of interband transitions under the in-plane tensile strain of the quantum-well heterojunction. The results are attributed to a change in the order of light- and heavy-hole bands caused by the tensile strain and to the formation of the ground state of charge carriers in the light-hole band. 相似文献
18.
L. S. Bovkun A. V. Ikonnikov V. Ya. Aleshkin S. S. Krishtopenko N. N. Mikhailov S. A. Dvoretskii M. Potemski B. Piot M. Orlita V. I. Gavrilenko 《JETP Letters》2018,108(5):329-334
Spectra of magnetoabsorption and Faraday rotation in HgTe/CdHgTe heterostructures with single and double quantum wells in high magnetic fields up to 11 T have been studied by the Fourier-transform spectroscopy method. The study of Faraday rotation spectra makes it possible to determine the sign of resonance circular polarization of transitions between Landau levels of carriers, which allows identifying observed intraband and interband transitions in the far and middle infrared ranges. 相似文献
19.
L.S. Bovkun A.V. Ikonnikov V.Ya. Aleshkin K.V. Maremyanin N.N. Mikhailov S.A. Dvoretskii S.S. Krishtopenko F. Teppe B.A. Piot M. Potemski M. Orlita V.I. Gavrilenko 《Opto-Electronics Review》2019,27(2):213-218
Magnetoabsorption in far and mid IR ranges in double HgTe/CdHgTe quantum wells with inverted band structure has been studied in high magnetic fields up to 30 T. Numerous intraband and interband transitions have been revealed in the spectra and interpreted within axial 8 × 8 k·p model. Splitting of dominant magnetoabsorption lines resulting from optical transitions from hole-like zero-mode Landau level has been discovered and discussed in terms of a built-in electric field and collective phenomena. 相似文献
20.
Effect of size and indium-composition on linear and nonlinear optical absorption of InGaN/GaN lens-shaped quantum dot 下载免费PDF全文
Based on the Schr ¨odinger equation for envelope function in the effective mass approximation, linear and nonlinear optical absorption coefficients in a multi-subband lens quantum dot are investigated. The effects of quantum dot size on the interband and intraband transitions energy are also analyzed. The finite element method is used to calculate the eigenvalues and eigenfunctions. Strain and In-mole-fraction effects are also studied, and the results reveal that with the decrease of the In-mole fraction, the amplitudes of linear and nonlinear absorption coefficients increase. The present computed results show that the absorption coefficients of transitions between the first excited states are stronger than those of the ground states. In addition, it has been found that the quantum dot size affects the amplitudes and peak positions of linear and nonlinear absorption coefficients while the incident optical intensity strongly affects the nonlinear absorption coefficients. 相似文献