Founded on June 17, 1971.
- transport, optical and non-linear phenomena in bulk semiconductors with a complicated structure of energy bands and semiconductor heterostructures, which are caused by heating electrons using strong electric or infrared light fields;
- phenomena of spatial self organization in the systems of non-equilibrium charge carriers in semiconductors and heterostructures;
- inversion of the charge carrier distribution and investigation of IR electromagnetic radiation in semiconductors and heterostructures;
- properties of nanocomposite materials.
- It was shown that an equilibrium violation in the system of electrons in a multi-valley semiconductor under the conditions of heating electrons leads to the multi-value anisotropy in electric conduction and unusual characteristics of transport phenomena, in particular, to the linear dependence of magnetoresistance on the magnetic field.
- A new kind of dissipative structures in the bipolar plasma of multi-valley semiconductor was found: transverse high-field and longitudinal current thermodiffusion autosolitons.
- In semiconductors with the degenerate valence band, a new mechanism of single-particle non-screened light scattering by free holes was found, which is caused by the scattering at quadrupole momentum density fluctuations in the course of intra-subband transitions.
- An anisotropic and non-linera character of the refractive index and the absorption coefficient, which is connected with the redistribution of electrons heated by the light-wave field among the equivalent valleys, was experimentally proved.
- It was established that the ionization energy of a shallow acceptor impurity in a quantum well of heterostructure is lower than that in the bulk of the material used for the well layer. It was shown that the effect is caused by a decrease in the effective mass of charge carriers due to an internal stress in the structure.
- It was shown theoretically that the binding energy of an electron with a shallow impurity in the quantum well of semiconductor heterostructure depends on the extent of impurity ionization. The effect is caused by the change in the well potential profile made by the space charge field that appears owing to the impurity ionization.
- It was shown experimentally that the low-temperature comductivity in heterostructures with delta-doped quantum wells subjected to a lateral electric field occurs both via the size-quantization subbands and via the impurity band.
- The usage of semiconductor heterostructures with quantum wells and deltadoped barriers for obtaining an effective real-space transfer of charge carriers initiated by the applied longitudinal electric field or the temperature was proposed and substantiated. A number of effects connected with the real-space transfer of carriers from the structure wells into the wells in the impurity deltalayers were found: the appearance of positive magnetoresistance and the nonlinear current dependence on the electric field.
- It was established experimentally that the electromagnetic emission by hot electrons in the course of non-direct intra-subband transitions in the quantum wells of heterostructures may be polarized along the direction of the lateral heating electric field. This phenomenon is connected with the deformation of the distribution function of carrier momenta in the electric field.
- In collaboration with scientists of the German Academy of Sciences and the Institute of semiconductors of NAS of Ukraine the phenomenon of multi-value anisotropy of the hot electron conductivity in multi-valley semiconductors is discovered and investigated (Diploma for Discovery No.284, 1984).
- It is shown that violation of equilibrium in the electron system of a multi-valley semiconductor under the conditions of the electrons heating leads to unusual characteristics of all transport properties, in particular, to appearance of a large magnetoresistance with a linear dependence on the magnetic field.
- A new kind of dissipative structures in the bipolar plasma of a multi-valley semiconductor is found: transverse high-field and longitudinal current thermo-diffusive autosolitons.
- A new mechanism of the single-particle non-screened light scattering by free holes caused by scattering due to fluctuations of the quadrupole moment density in the case of intrasubband transitions is found in semiconductors with a degenerate valence band.
- It is established that for semiconductors with a degenerate valence band the dependence of the plasmon frequency on the carrier concentration is weaker as compared to the expected root-like dependence. It is shown that the effect is caused by contribution of transitions between the light and heavy hole subbabnds into the dielectric permittivity of a crystal.
- Existence of anisotropy and non-linearity of the refraction index and absorption coefficient in the multi-valley semiconductors connected with redistribution of electrons among equivalent valleys in consequence of heating by light wave field is experimentally proved.
- Stabilization of the low-frequency instabilities in the liquid crystals by the high frequency electric field is implemented.
- For the porous silicon the birefringence in the visible spectral range is found which is comparable by the order of magnitude with the quartz crystal.
- The dependence of the binding energy of an acceptor impurity and the localization radius of charge carriers on impurities on the position of an impurity atom in the quantum well is found.
- V.М.Poroshin, V.M.Vasetskii. Infrared phase-conjugate reflection by hot electrons induced optical nonlinearity in n-Ge. Applied Physics B72, p.323, 2001.
- M.Ashe, O.G.Sarbey. Influrnce of carrier heating on potential well depth and screening in highly planar-doped GaAs:Si. Physica B314, р.207, 2002.
- V.N.Poroshin, A.V.Gaydar. Band structure effects in light scattering by plasmons in p-type germanium. Ukr.J.Phys., v.49, № 1, p.94, 2004.
- M.Asche, B.Danilchenko, I.Chernobryvcev, D.Poplavskyy and O.Sarbey. Phonon spectroscopy of carrier heating effects in d-dopped GaAs:Si. Sol.St. Phys., v.19, р.25, 2004.
- V.V.Vainberg, Yu.N.Gudenko, P.A.Belevski, M.N.Vinoslavski, V.N.Poroshin, V.M.Vasetski. Current oscillation and high field domains in the InGaAs/GaAs heterostructures with ?-dopped quantum well. Nanosystems, Nanomaterials, Nanotechnologies, v.4, № 1, p.1001, 2006.
- M.N.Vinoslavskii, P.A.Belevski, A.V.Kravchenko,.Autosolitons in electron- hole plasma in p-Ge .Zh. Eksp. Teor. Fiz, v.129, p.477, 2006.
- V.V.Vainberg, Yu.N.Gudenko, V.N.Poroshin, , V.N. Tulupenko H.H.Cheng, Z.P.Yang, V.Mashanov, and K.Y.Wang. Energy characteristics of impurity boron in Si/Si1?xGex heterostructures with on-center and on-edge selective doping of quantum wells. Low Temperature Physics, v..33, p.1143, 2007.
- P.A.Belevskii, V.V.Vainberg, M.N.Vinoslavskii, A.V.Kravchenko, V.N.Poroshin, O.G.Sarbey. Real-space transfer and far-infrared emission of hot electrons in the InGaAs/GaAs heterostructures with tunnel-coupled quantum wells. Ukr.J.Phys., v.54, № 1-2, p.122, 2009.
Laureate of the State Prize of Ukraine in Science and Technology
Dr. Sci. Professor Oleg G. Sarbey.
Left to right: graduate Bilovskyy P., Vinoslavs'ka M., Kravchenko A.
Shahovtsova S. and Poroshin V.
Left to right: Weinberg V., Vasetskyy B., Poroshin V.
Chernomorets N. and Kovalchuk D.
Collective photo of department