A5085960854- Semiconductor Quantum Structures and Devices
- Advanced Semiconductor Detectors and Materials
- Spectroscopy and Laser Applications
- Topological Materials and Phenomena
- Terahertz technology and applications
- Quantum and electron transport phenomena
- Photonic and Optical Devices
- Silicon Nanostructures and Photoluminescence
- Semiconductor materials and interfaces
- Semiconductor Lasers and Optical Devices
- Graphene research and applications
- Physics of Superconductivity and Magnetism
- Spectroscopy and Quantum Chemical Studies
- Surface and Thin Film Phenomena
- 2D Materials and Applications
- GaN-based semiconductor devices and materials
- Atmospheric Ozone and Climate
- Semiconductor materials and devices
- Laser Design and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Magnetic properties of thin films
- Superconducting and THz Device Technology
- Phase-change materials and chalcogenides
- Advancements in Semiconductor Devices and Circuit Design
- Silicon and Solar Cell Technologies
Institute for Physics of Microstructures
2016-2025
Institute of Superhigh-Frequency Semiconductor Electronics of the Russian Academy of Sciences
2024
N. I. Lobachevsky State University of Nizhny Novgorod
2015-2024
Institute of Applied Physics
1983-2023
Institute of Physical Materials Science
2022
Ioffe Institute
2022
Russian Academy of Sciences
2001-2021
Institute of Semiconductor Physics
1986-2021
Williams (United States)
2019
Yaroslav-the-Wise Novgorod State University
2016-2018
Recently, a new class of materials, so-called topological insulators, has emerged. These are systems characterized by the inversion electronic band structure and also certain strength spin-orbit interaction. HgTe/Cd${}_{x}$Hg${}_{1\ensuremath{-}x}$Te quantum wells represent prominent example. They can change to insulator phase from conventional when thickness well is increased over critical ${d}_{c}$ = 6.3 nm. Here, we report on far-infrared magnetospectroscopy study set with different...
It has recently been shown that the electronic states in bulk gapless HgCdTe offer another realization of pseudo-relativistic three-dimensional particles a condensed matter system. These single valley relativistic states, referred to as massless Kane fermions, cannot be described by any other well-known particles. Furthermore, band structure can continuously tailored modifying either cadmium content or temperature. At critical concentration temperature, bandgap, Eg, collapses system...
We report numerical calculations of the frequency-dependent dielectric function for different gauges electromagnetic field in optical transition operator. Comparing results, we draw conclusions about importance nonlocality effects entering calculations. Apart from spatial inhomogeneity related to atomic structure matter, they are due nonlocal pseudopotentials, quasiparticle self-energies, and incompleteness basis functions. Besides their influence on spectra, effect validity f-sum rule...
We present theoretical investigations of pressure and temperature driven phase transitions in HgTe quantum wells grown on CdTe buffer. Using the 8-band \textbf{k$\cdot$p} Hamiltonian we calculate evolution energy band structure at different well width with hydrostatic up to 20 kBar ranging 300 K. In particular, show that addition temperature, tuning allows drive between semimetal, insulator topological phases. Our realistic calculations reveal inversion under may be accompanied by non-local...
We report on stimulated emission at wavelengths up to 19.5 μm from HgTe/HgCdTe quantum well heterostructures with wide-gap HgCdTe dielectric waveguide, grown by molecular beam epitaxy GaAs(013) substrates. The mitigation of Auger processes in structures under study is exemplified, and the promising routes towards 20–50 wavelength range, where lasers may be competitive prominent emitters, are discussed.
Due to their specific physical properties, HgCdTe-based heterostructures are expected play an important role in terahertz photonic systems. Here, focusing on gated devices presenting inverted band ordering, we evidence enhancement of the photoconductive response close charge neutrality point and at magnetic field driven topological phase transition. We also show ability these be used as imagers. Regarding emitters, present results stimulated emission HgCdTe conventional semiconductor state...
Amplified interband emission within the 14–24 μm range is investigated in HgCdTe-based quantum wells under optical pumping. Carrier lifetimes are shown to be marginally limited only by Shockley–Read–Hall recombination, fully realizing advantage of relativistic energy spectra 2D HgCdTe terms suppressing Auger processes. By carefully optimizing waveguides and mitigating carrier heating, we achieve amplification thresholds as low 1.5–2 W/cm2 at a pulse duration 20–500 μs. With last generation...
We report on the temperature-dependent magnetospectroscopy of two HgTe/CdHgTe quantum wells below and above critical well thickness ${d}_{c}$. Our results, obtained in magnetic fields up to 16 T s temperature range from 2 150 K, clearly indicate a change band-gap energy with temperature. A wider than ${d}_{c}$ evidences temperature-driven transition topological insulator semiconductor phases. At 90 merging inter- intraband transitions weak specifies formation gapless state, revealing...
Гетероструктуры с квантовыми ямами на основе твердых растворов HgCdTe в последнее время рассматриваются как перспективный материал для приложений среднего инфракрасного диапазона, частности, создания лазеров. В данной работе исследовано влияние процессов фотолитографии различными масками и ионного травления оптические свойства мезаструктур микродисковыми, микрокольцевыми гребенчатыми резонаторами, сформированных гетероструктур HgCdTe/CdHgTe. Показана возможность использования предлагаемой...
Lasing from HgCdTe microdisc cavities is demonstrated at wavelengths as long 22 — 25 μm. The optical threshold and operation temperature are far being limited by intrinsic recombination processes. employed ion etching technology appears to introduce additional defects in the vicinity of microdiscs, degrading figures merit height cavity increases. However, a watt-level mid-infrared pumping source should suffice for lasing microdiscs with moderate ~100 μm diameter.
Lasing from HgCdTe microdisk cavities is demonstrated at wavelengths as long 20–25 μm. The optical threshold and operation temperature are mainly limited by nonradiative Shockley–Read–Hall type recombination. employed ion etching technology appears to introduce additional defects in the vicinity of microdisks, degrading figures merit height cavity increases. However, a watt-level mid-infrared pumping source should suffice for lasing microdisks with ∼3 ∼100 μm diameter.
The linear optical response of semiconductors has been studied beyond the density-functional theory with ab initio pseudopotentials and random-phase approximation. Effects macroscopic local fields microscopic exchange-correlation interaction are included in description spectra. Quasiparticle corrections to single-particle energies have added polarization function. Numerical calculations performed for group-IV materials Si, SiC, diamond as model substances. In static limit low-frequency...
The authors report on the demonstration of room temperature, tunable terahertz detection obtained by 50nm gate length AlGaAs∕InGaAs high electron mobility transistors (HEMTs). They show that physical mechanism is related to plasma waves excited in transistor channel and increasing drain current leads transformation broadband resonant one. also cap layer regions significantly affect oscillation spectrum HEMTs decreasing frequencies.
We investigate experimentally transport in gated microsctructures containing a band-inverted HgTe/Hg${}_{0.3}$Cd${}_{0.7}$Te quantum well. Measurements of nonlocal resistances using many contacts prove that the depletion regime current is carried by edge channels, as expected for two-dimensional topological insulator. However, high and nonquantized values channel show protection length (i.e., distance on which carriers helical channels propagate without backscattering) much shorter than...
Abstract Cyclotron resonance study of HgTe/CdTe-based quantum wells with both inverted and normal band structures in quantizing magnetic fields was performed. In semimetallic HgTe structure, a hole cyclotron line observed for the first time. samples interband transitions were wide width due to well fluctuations. all samples, impurity-related magnetoabsorption lines revealed. The obtained results interpreted within Kane 8·8 model, valence offset CdTe HgTe, parameter E P being adjusted.
The discovery of Dirac fermions in a number 2D and 3D materials boosted the solid-state research an unprecedented way. Among many hopes using their exceptional physical properties, it has been argued that reduced nonradiative losses would allow graphene to compete with quantum cascade lasers (QCLs) race for terahertz (THz) emitters. Unfortunately, Auger recombination (AR) process is still active massless gapless graphene. However, massive fermions, AR can be entirely suppressed below certain...
Cyclotron resonance spectra of 2D electrons in HgTe/CdxHg1−xTe (0 1 3) quantum well (QW) heterostructures with inverted band structure have been thoroughly studied quasiclassical magnetic fields versus the electron concentration varied using persistent photoconductivity effect. The cyclotron mass is shown to increase QW width contrast QWs normal structure. measured values are be systematically less than those calculated 8 × Kane model conventional set HgTe and CdTe material parameters. In...
Photoluminescence (PL) and photoconductivity (PC) studies of Hg1−xCdxTe (0.19 ≤ x 0.23) epitaxial films are presented. Interband PL is observed at wavelengths from 26 to 6 μm in the temperature range 18 K–200 K. The line full width half maximum about meV (4kT) K approaches its theoretical limit 1.8kT higher temperatures. Carrier recombination process also investigated by time resolved PC pulsed excitation. Radiative transitions shown be dominating mechanism carrier high excitation levels.
Stimulated emission from waveguide HgCdTe structures with several quantum wells inside core is demonstrated at wavelengths up to 9.5 μm. Photoluminescence line narrowing down kT energy, as well superlinear rise in its intensity evidence the onset of stimulated emission, which takes place under optical pumping small ∼0.1 kW/cm2 18 K and 1 80 K. One can conclude that potential for long-wavelength lasers not exhausted.
Abstract Even‐order non‐linear optical spectroscopy has emerged as an unusually sensitive technique for non‐invasive analysis of surfaces and buried interfaces centrosymmetric materials. The forefront challenges are: to develop reliable microscopic computational methods calculating interpreting measured surface spectra; relate spectra quantitatively linear probes such reflectance‐difference (RDS); convenient acquiring over bandwidths (several electron‐volts) that encompass multiple...
Photoluminescence (PL) spectra and kinetics of narrow gap Hg1−xCdxTe/CdyHg1−yTe quantum well (QW) heterostructures grown by molecular beam epitaxy technique are studied. Interband PL observed from 18 K up to the room temperature. Time resolved studies reveal an additional line with slow (7 μs at K) related deep defect states in barrier layers. These act as traps counteracting carrier injection into QWs. The decay time signal QW layers is about 5 showing that gain can be achieved wavelengths...
Investigation into far infrared photoconductivity (PC) in narrow-gap epitaxial bulk Hg1–xCdxTe (x < 0.2) films grown by molecular beam epitaxy and chemical vapor deposition techniques is presented. A broadband of photosensitivity terahertz region found at 4.2 77 K. Some long-wavelength peculiarities spectra are discovered their origins discussed. We also study PC relaxation process with nanosecond time resolution. It that carrier non-radiative measured lifetimes show some the structures...