A5079854249- Semiconductor Quantum Structures and Devices
- Silicon Nanostructures and Photoluminescence
- Terahertz technology and applications
- GaN-based semiconductor devices and materials
- Photonic and Optical Devices
- Semiconductor materials and interfaces
- Plasmonic and Surface Plasmon Research
- Thermal Radiation and Cooling Technologies
- Phase-change materials and chalcogenides
- Advanced Semiconductor Detectors and Materials
- Topological Materials and Phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Quantum and electron transport phenomena
- Silicon Carbide Semiconductor Technologies
- Magnetic Field Sensors Techniques
- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Advanced ceramic materials synthesis
- Solid-state spectroscopy and crystallography
- Thermal properties of materials
- Magneto-Optical Properties and Applications
- Spectroscopy and Laser Applications
- 2D Materials and Applications
- Photocathodes and Microchannel Plates
- Electromagnetic Effects on Materials
University of Regensburg
2023-2024
Peter the Great St. Petersburg Polytechnic University
2014-2023
Russian Academy of Sciences
2000
Institute for Physics of Microstructures
1995-1999
Institute of Applied Physics
1994
The circular photon drag effect is observed in a bulk semiconductor. photocurrent caused by transfer of both translational and angular momenta light to charge carriers detected tellurium the midinfrared frequency range. Dependencies on polarization incidence angle agree with symmetry analysis effect. Microscopic models are developed for intra- intersubband optical absorption valence band tellurium. shift contribution current calculated. An decrease increase energy explained theory...
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 terahertz spectra up 4 times selective amplification vicinity plasmon resonance. This shown be frequency-controllable period. Exact spectral positions resonances preliminarily experimentally detected help...
We report a comprehensive study of polarized infrared/terahertz photocurrents in bulk tellurium crystals. observe different photocurrent contributions and show that, depending on the experimental conditions, they are caused by trigonal photogalvanic effect, transverse linear photon drag magnetic field induced circular effects. All observed have not been reported before well explained developed phenomenological microscopic theory. that effects can be unambiguously distinguished studying...
Terahertz time-domain spectroscopy and Fourier-transform infrared were developed as the method for investigation of high-frequency characteristics two-dimensional electron gas GaN:C buffer layers in AlGaN/AlN/GaN heterostructures grown on a semi-insulating SiC substrate. The reflectance transmittance spectra selected heterostructure studied after top removed by reactive ion etching. Results numerically analyzed using transfer matrix taking into account conductivity via Drude model complex...
We report on experimental studies of the surface plasmon-phonon polariton excitations in heavily doped GaAs epitaxial layers. Reflection and emission radiation frequency range 2-19 THz were investigated for samples with surface-relief grating, as well planar surface. The reflectivity spectrum p-polarized measured sample grating demonstrates a set resonances attributed to different modes. observed lie beyond limits Reststrahlen band. Terahertz from was studied nonequilibrium conditions under...
Optical properties of a heavily-doped GaAs epitaxial layer with regular grating at its surface have been experimentally investigated in the terahertz spectral range. Reflectivity spectra for profiled drastically differ from those as-grown epilayer planar surface. For s-polarized radiation, this difference is totally caused by electromagnetic wave diffraction grating. p-polarized additional resonant dips arise due to excitation plasmon-phonon polaritons. Terahertz radiation emission under...
We report on the observation of circular photon drag effect in a bulk semiconductor. The photocurrent caused by transfer both linear and angular momenta photons to charge carriers is detected tellurium. Dependencies light polarization incidence angle agree with symmetry analysis effect. Experimental spectral data mid-infrared range qualitatively microscopic model considering intersubband optical transitions holes
We report the studies on optical properties of a GaN/AlGaN heterostructure with surface metal grating. The fabricated structures were optimized for observation 2D plasmon resonances in spectral range 2–5 THz. spectra equilibrium transmission experimentally investigated and resonance was found. current-voltage characteristics grating sample reference without measured dependence hot electron temperature electric field established. Terahertz electroluminescence studied both samples sensitivity...
Surface plasmon polaritons are investigated in heavily doped n-GaN epitaxial layers. The grating etched on the surface of layer is used to convert photons into and vice versa. spectral study reflection demonstrates possibility nonequilibrium excitation due terahertz radiation scattering grating. Terahertz electroluminescence under lateral electric field. luminescence spectrum a significant contribution polariton emission.
We report on the observation and comprehensive study of terahertz radiation induced magneto-photogalvanic effect (MPGE) in bulk CdHgTe crystals hosting Kane fermions. The MPGE has been detected Cd$_{x}$Hg$_{1-x}$Te films with Cd contents $x = 0.15$ $0.22$ subjected to an in-plane magnetic field. At liquid helium temperature we observed multiple resonances current upon variation In 0.22$ noninverted band structure, are caused by cyclotron resonance (CR) photoionization impurity level....
Nonlinear electron transport induced by polarized terahertz radiation is studied in two-dimensional tellurene at room temperature. A direct current, quadratic the radiation's electric field, observed. Contributions sensitive to helicity, polarization orientation as well independent current are found. We show that these contributions can be modified magnitude of external gate potential. demonstrate this terahertz-driven arises from Berry curvature dipole and side-jump microscopic...
Nonlinear electron transport induced by polarized terahertz radiation is studied in two-dimensional tellurene at room temperature. A direct current, quadratic the radiation's electric field, observed. Contributions sensitive to helicity and polarization orientation as well independent current are found. We show that these contributions can be modified magnitude of external gate potential. demonstrate this terahertz-driven arises from Berry curvature dipole side-jump microscopic mechanisms.
The weakest mode of the infrared active folded phonons in 4H–SiC, transverse acoustic (FTA) mode, has been experimentally studied. lifetime FTA determined. is 58 ± 4 ps at room temperature and increases to 140 7 when decreased 5 K. These results were obtained by experimental study far-infrared transmission SiC crystal its theoretical simulation using an oscillator model for dielectric function around phonon resonance. was a fitting parameter analyzing irregular interference pattern spectrum...
Far-infrared photoconductivity spectra of strained multi-quantum well Ge/Ge1—xSix (≈︂ 0.1) heterostructures resulting from the excitation shallow acceptors were investigated. The are shown to be shifted long-wavelength end far-infrared range if compared with in bulk p-Ge due splitting light and heavy holes subbands Ge layers owing “built-in” deformation size quantization. acceptor germanium under uniaxial tension, that is “equivalent” heterostructures, calculated by variational technique;...
We report on the study of far-infrared transmission in silicon carbide 6H polytype region IR active folded transverse acoustic (FTA) phonon doublet. Joint analysis transmittance spectra obtained at low and high resolutions is performed to determine spectral dependences refractive index absorption coefficient. A dual Lorentz oscillator model used simulate FTA contributions dielectric function. The strengths lifetimes for both components doublet 6H-SiC are determined. At temperature decrease...
Optical transmission and reflection for a single GaN/AlGaN heterojunction grown on sapphire have been investigated with high low spectral resolution in the range of 8–47 meV. For comparison, same spectra measured substrate. Refractive index dispersion has determined from resolution. Then data 2D electron absorption were obtained spectra. The terahertz emission under heating strong electric field first time.
Cyclotron resonance of photoexcited carriers in Ge/Ge 1- x Si multilayer strained undoped heterostructures (HSs) was investigated for the first time. line positive charge with effective mass m c ≈0.07 0 corresponding to that holes upper subband quantum wells Ge layers observed absorption and mm-photoconductivity spectra. The persistent photoconductivity is shown arise after interband illumination owing free remaining sample.
Surface plasmon polaritons in n-GaN are investigated. Experiments on optical reflection demonstrate the possibility of surface polariton excitation grating structure using terahertz radiation. Study radiation emission under lateral electric field shows that scattering hot makes a significant contribution to intensity. In certain spectral range this mechanism prevails.
Surface plasmon polaritons at the n-GaN/vacuum interface are investigated. Experimental studies of terahertz radiation reflection and emission performed on heavily silicon-doped GaN epitaxial layers grown sapphire substrates. To provide interaction THz with surface polaritons, a regular grating was fabricated outer layer. Study from microstructures under lateral electric field shows that scattering non-equilibrium makes significant contribution to intensity.
Variation of absorption terahertz radiation in lateral electric field was investigated GaN epitaxial layers. Different behaviour the modulation observed for polarized along and perpendicular to it. Joint analysis optical transport measurements let us obtain dependencies mobility, electron concentration cross-section. For field, results are accordance with Drude model free absorption. Another polarization demonstrates significant deviation that is yet be studied more thoroughly.