A5071913780- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Advanced Semiconductor Detectors and Materials
- Quantum Dots Synthesis And Properties
- Strong Light-Matter Interactions
- Chalcogenide Semiconductor Thin Films
- Quantum optics and atomic interactions
- Semiconductor Lasers and Optical Devices
- Electronic and Structural Properties of Oxides
- Spectroscopy and Quantum Chemical Studies
- Nanowire Synthesis and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Magneto-Optical Properties and Applications
- Molecular Junctions and Nanostructures
- Thermal Radiation and Cooling Technologies
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Graphene research and applications
- Atomic and Molecular Physics
- Advancements in Semiconductor Devices and Circuit Design
- ZnO doping and properties
- Diamond and Carbon-based Materials Research
- Electromagnetic Effects on Materials
- Thermal properties of materials
- Neural Networks and Reservoir Computing
Ioffe Institute
2014-2024
Physico-Technical Institute
2005-2020
St Petersburg University
2006-2020
Institute of Physics
1998-2020
Polish Academy of Sciences
1998-2020
Centre National de la Recherche Scientifique
1993-2020
Institut Néel
2020
Russian Academy of Sciences
2001-2014
Petersburg Nuclear Physics Institute
2014
Physical and Technical Institute
2011-2013
Excitons and charged excitons (trions) are investigated in ZnSe-based quantum well structures with (Zn,Be,Mg)Se (Zn,Mg)(S,Se) barriers by means of magneto-optical spectroscopy. Binding energies negatively ${(X}^{\ensuremath{-}})$ positively ${(X}^{+})$ measured as functions width, free carrier density external magnetic fields up to 47 T. The binding energy ${X}^{\ensuremath{-}}$ shows a strong increase from 1.4 8.9 meV decreasing width 190 $29 \AA{}.$ ${X}^{+}$ about 25% smaller than the...
Resonance-reflectivity data on CdTe/(Cd,Mn)Te quantum wells and superlattices are analyzed to obtain the exciton longitudinal-transverse splitting or oscillator strength as a function of layer widths and/or band offsets altered by externally applied magnetic fields. A nonlocal-dielectric-response theory for single concept an optically homogeneous dielectric medium formulated periodic structures developed. Strong effects magnetic-field-induced type-I--type-II transition spin-superlattice...
Spin-relaxation times of two-dimensional electrons in asymmetrical (001) AlGaAs quantum wells are measured by means Hanle effect. Three different spin-relaxation for spins oriented along [110], $[1\overline{1}0]$, and [001] crystallographic directions extracted demonstrating anisotropy the D'yakonov-Perel' spin relaxation mechanism. The relative strengths Rashba Dresselhaus terms describing spin-orbit coupling semiconductor well structures obtained. It is shown that splitting about four...
The circularly polarized photoluminescence (PL) of excitons induced by application a magnetic field is investigated experimentally and theoretically for an inhomogeneous ensemble (In,Al)As/AlAs quantum dots with indirect band gap type-I alignment. We demonstrate that the circular polarization degree PL shows nonmonotonic dependence on dot size splitting oppositely emission bands significantly larger than Zeeman in individual dots. low-energy luminescence has lower intensity high-energy one....
A combined exciton-cyclotron resonance is found in photoluminescence excitation and reflectivity spectra of semiconductor quantum wells containing an electron gas low density. In external magnetic fields, incident photon creates exciton the ground state simultaneously excites one resident electrons from lowest to upper Landau levels. theoretical model developed, which gives a good quantitative description energy position intensity resonance.
We report on magneto-optical studies of ZnSe/(Zn,Mg)(S,Se) quantum wells with n-type and p-type modulation doping. Negatively positively charged excitons related to the heavy-hole exciton states are found identified by their polarization properties. formed light-hole observed. Their binding energy is about 20% less than that exciton. The trion parameters (radiative nonradiative dampings) determined.
The oscillator strength of negatively charged excitons (trions) in ZnSe/(Zn,Mg)(S,Se) quantum-well structures with n-type modulation doping is studied by means reflectivity as a function electron concentration, temperature, and external magnetic fields. trion found to increase linearly increasing concentration up $6\ifmmode\times\else\texttimes\fi{}{10}^{10}{\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}.$ nonradiative damping shows no dependence on the or field. An optical method, based analysis...
The quantum confined Pockels effect has been observed in type-II ZnSe/BeTe well structures. In order to describe the in-plane optical anisotropy induced by electric field heterostructures, a theoretical approach developed which is based on representation of matrix elements microscopical tight-binding model. It shown that polarized light spectroscopy allows one obtain microscopic information interfaces especially orientation chemical bonds.
An optical method is suggested to determine the concentration of two-dimensional electrons in modulation-doped quantum wells at low and moderate electron densities between 10^{9} 2x10^{11} cm^{-2}. The based on an analysis magneto-reflectivity spectra charged excitons (trions). circular polarization degree oscillator strength contain information about density spin gas. applied CdTe/(Cd,Mg)Te ZnSe/Zn,Mg)(S,Se) heterostructures.
A concept of mixed exciton-trion states is formulated theoretically and proved experimentally for II–VI semiconductor quantum wells with a two-dimensional electron gas. The considers the resonances neutral excitons charged (trions) as (with each other) via their interaction free electrons. Reflectivity spectra modulation-doped ZnSe/(Zn,Mg)(S,Se) CdTe/(Cd,Mg)Te are analyzed. good qualitative agreement experimental results model calculations achieved.
We report the photoluminescence characterization of GaAs quantum dots embedded in AlGaAs nanowires. Time-integrated and time-resolved was measured for both arrays single dot/nanowires. The optical spectroscopy data show influence growth temperature on distribution diameters presence different crystalline phases By means scanning transmission electron microscopy we observed that has a strong homogeneity nanowires, size density. In spectra dot, spectral diffusion exciton line. Formation...
Time-resolved and cw photoluminescence (PL) spectra are studied in type-II ZnSe/BeTe multiple quantum wells. Samples with nonequivalent interfaces exhibit a strong in-plane linear polarization of the PL along $〈110〉$ axis. The is stable respect to an increase excitation intensity by many orders magnitude, raising temperature up 300 K not influenced applied electric or magnetic fields. experimental data discussed framework tight-binding model taking into account band alignment lack common...
We report a remarkable enhancement of the magnetic moments excitons as result their motion. This surprising result, which we have observed in magneto-optical studies three distinct zinc-blende semiconductors, GaAs, CdTe, and ZnSe, becomes significant kinetic energy exciton comparable with its Rydberg is attributed to motionally induced changes internal structure exciton. The moment function translational wave vector can be represented by universal equation.
The magnetic field effect on phase transitions in electrically neutral bosonic systems is much less studied than those fermionic systems, such as superconducting or ferromagnetic transitions. Nevertheless, composite bosons are strongly sensitive to fields: both their internal structure and motion whole particles may be affected. A joint effort of ten laboratories has been focused studies polariton lasers, where non-equilibrium Bose-Einstein condensates quasiparticles, exciton-polaritons,...
We report on the observation of optical activity quantum wells resulting in conversion light polarization state controlled by propagation direction. The is detected reflection measurements. show that a pure $s$-polarized incident well reflected as an elliptically polarized wave. signal drastically enhanced vicinity light-hole exciton resonance. caused spin-orbit splitting hole states and birefringence studied structure. bulk inversion asymmetry constant...
Photoluminescence (PL) and reflectivity spectra from modulation-doped $\mathrm{Cd}\mathrm{Te}∕{\mathrm{Cd}}_{x}{\mathrm{Mg}}_{1\ensuremath{-}x}\mathrm{Te}$ quantum well structures containing a two-dimensional electron gas have been studied in magnetic fields up to $45\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. In high fields, the recombination dark triplet trion state was found be one of most intense PL lines. A ``bright'' line is revealed both above $35\phantom{\rule{0.3em}{0ex}}\mathrm{T}$....
Abstract The linear optical properties of short‐period GaAs/AlGaAs superlattices (SL) with three‐dimensional conduction minibands are studied. Using spectroscopy p‐polarized reflectance at oblique incidence the enhancement exciton resonance features and effect lineshape inversion Brewster angle for first time observed. heavy‐ light‐hole oscillator strength is found to decrease shortening SL period. orientation technique splitting electron in wave vector measured time. An essential increase...
Very large changes in the Zeeman splittings and diamagnetism of excitons as they acquire kinetic energy wide quantum wells CdTe are reported. The found to be functions translational wave vector ${K}_{z}$ exciton growth direction well, irrespective width also strong magnetic field. behavior is accounted for by a model which mixing occurs between hydrogenic states describe center mass or adiabatic approximation. ascribed terms arise Luttinger Hamiltonian when it extended excitons. Excellent...
Circularly and linearly polarized radiation due to spatially indirect optical transitions is studied in semimagnetic (Zn,Mn)Se/BeTe nonmagnetic ZnSe/BeTe quantum-well structures with a type-II band alignment. Because of the giant in-plane anisotropy matrix elements related particular interface, complete spin orientation photocarriers induced by magnetic fields leads not purely circular but instead elliptical polarization luminescence. From comparison between theory experiment parameter...
The formation of two-dimensional negatively charged excitons (negative trions) out and free electrons is found to be determined by a dynamical equilibrium. This equilibrium consists chemical equilibrium, relating the trion, exciton, electron populations, modified finite recombination times (charged) excitons, as evidenced magnetic-field-dependent photoluminescence (PL) far-infrared study doped CdTe/CdMgTe quantum wells. data show that trion entirely driven occupation spin-split exciton...
The magnetic properties of heavy-hole excitons in wide quantum wells ZnTe with Zn${}_{x}$Mg${}_{1\ensuremath{-}x}$Te barriers have been studied photoluminescence and reflectivity measurements. exciton moments (as characterized by the $g$ values) diamagnetic shifts transitions are found to depend strongly on wave-vector component ${K}_{z}$ associated translational motion normal plane well. case differs from examples this behavior previously reported for GaS, CdTe, ZnSe since is under tensile...