arXiv subjects

G. N. Logvinov

Publications and source records attributed to G. N. Logvinov.

8 recordsLinked to original sources

arXiv2004

Recombination and Lifetimes of Charge Carriers in Semiconductors

In this Communication, it is shown that models used for describing generation and recombination of electrons and holes lead to disagreements with Maxwell's electrodynamics. Self-consistent expressions, more adequately depicting the actual physical processes of electron-hole recombination in semiconductors are obtained. It is shown that the electron and hole lifetimes can be defined correctly only for the special cases when the electron and hole nonequilibrium concentrations are the same, these lifetimes being equal. The influence of temperature inhomogeneity on the recombination is also considered. The recombination rate for hot electrons is obtained in the case when the electron and hole temperatures differ.

cond-mat.soft↗

arXiv2002

Electron and Phonon Temperature Relaxation in Semiconductors Excited by Thermal Pulse

Electron and phonon transient temperatures are analyzed in the case of nondegenerate semiconductors. An analytical solution is obtained for rectangular laser pulse absorption. It is shown that thermal diffusion is the main energy relaxation mechanism in the phonon subsystem. The mechanism depends on the correlation between the sample length and the electron cooling length in an electron subsystem. Energy relaxation occurs by means of the electron thermal diffusion in thin samples (), and by means of the electron-phonon energy interaction in thick samples (). Characteristic relaxation times are obtained for all the cases, and analysis of these times is made. Electron and phonon temperature distributions in short and long samples are qualitatively and quantitatively analyzed for different correlations between the laser pulse duration and characteristic times.

cond-mat↗

arXiv2002

"Resonance" phenomena in thermal diffusion processes in two-layer structures

The dependence on chopper frequency of the effective thermal diffusivity and effective thermal conductivity in photoacoustic experiments is discussed. The theoretical model of a two-layer structure at rear-surface illumination in the high frequency limit is considered. It is shown that the effective thermal diffusivity presents ``resonance'' while the effective thermal conductivity sharply changes its magnitude and sign. Such ``resonant'' behavior strongly depends on the surface thermal conductivities associated with the interface thermal contacts.

cond-mat↗

arXiv2002

The Role of Non-Equilibrium Carriers in Formation of Thermo-E.M.F. in Bipolar Semiconductors

A new approach to thermoelectric phenomena, as a linear transport process of non-equilibrium charge carriers, is presented. The role of non-equilibrium carriers, as well as surface and bulk recombination, is demonstrated to be crucial even within a linear approximation. Electron and hole Fermi quasi-levels appeared in a thermal field are calculated in the case of thermoelectric current flow through a circuit. It is shown, for the first time, that the Fermi quasi-level of one of subsystem of quasi-particles can be a non-monotonic function of the coordinates. General expressions for the thermoelectric current, thermo-e.m.f., and electrical resistance of bipolar semiconductors have been obtained. For the first time the surface recombination and surface resistance were taken into account.

cond-mat↗

arXiv2002

New physical principles of contact thermoelectric cooling

We suggest a new approach to the theory of the contact thermoelectric cooling (Peltier effect). The metal-metal, metal-n-type semiconductor, metal-p-type semiconductor, p-n junction contacts are analyzed. Both degenerate and non-degenerate electron and hole gases are considered. The role of recombination in the contact cooling effect is discussed by the first time.

cond-mat↗

arXiv1997

Spatially nonuniform energy distribution of electrons in a submicron semiconductor film

The symmetric part of the distribution of the electrons in a semiconductor submicron film, placed between a heater and refrigeration unit, is derived and analyzed. It is shown that, in general, it is of non-Fermi (non-Maxwellian) nature. A new mechanism is proposed to account for the non-Maxwellian form of the symmetric part of the distribution function. This mechanism is based on the different energy dependences of the momentum relaxation time in the bulk of the semiconductor and its skin layer.

cond-mat↗

arXiv1997

Theory of thermoelectric effects when the temperature approximation is incorrect

The flow of a thermoelectric current through a semiconductor of submicron dimensions is analyzed. The rate of surface relaxation of the energy is assumed to be much higher than the rate of electron-electron collisions. Under these conditions, it is incorrect to describe the electron gas by means of a Maxwellian distribution and thus to describe the thermoelectric effects in terms of an electron temperature and a chemical potential. A theory is derived for these effects. This theory does not include the latter parameters and is based on a non-Maxwellian distribution which is spatially nonuniform in terms of energy.

cond-mat↗

arXiv1995

The Nature of Thermopower in Bipolar Semiconductors

The thermoemf in bipolar semiconductors is calculated. It is shown that it is necessary to take into account the nonequilibrium distribution of electron and hole concentrations (Fermi quasilevels of the electrons and holes). We find that electron and hole electric conductivities of contacts of semiconductor samples with connecting wires make a substantial contribution to thermoemf.

cond-mat↗