Yuri G. Gurevich

Center for Research and Advanced Studies of the National Polytechnic Institute | Cinvestav · Departamento de Física

This study is focused on a new method to determine the thermo-electromotive force (thermo-E.M.F.) of a non-degenerate bipolar semiconductor taking into account recombination heat of non-equilibrium carriers, the non-linear temperature distribution with respect to position, and the existence of two different quasi-levels of Fermi for electrons and h...

Compared to other energy conversion devices, the efficiency of thermoelectric generators (TEGs) is relatively low. Thus, several papers have sought to improve device performance by investigating the effects of Thomson effect on thermoelectric efficiency. However, the synergistic relationship between the temperature dependent Seebeck coefficient (SC...

Joule heating of a homogeneous bipolar semiconductor leads to the appearance of nonequilibrium spatially inhomogeneous current carriers. Both energetic and concentration nonequilibrium states arise. Temperature and concentration gradients at the boundaries always have opposite signs. The concentration will become lower in heated regions, while it w...

Numerous previous studies indicate that the performances of thermoelectric generators are enhanced by incorporating legs with variable area geometries. However, there is a dearth of comprehensive optimisation studies on these new thermoelectric generator designs. More so, the few optimisation studies that exist have rather employed unrealistic isot...

Numerous previous studies indicate that the performances of thermoelectric generators are enhanced by incorporating legs with variable area geometries. However, there is a dearth of comprehensive optimisation studies on these new thermoelectric generator designs. More so, the few optimisation studies that exist have rather employed unrealistic isot...

Supplementary material showing governing equations, performance data, and results.

In this work it is shown that temperature inhomogeneity in an homogeneous bipolar semiconductor sample leads to a spatial variation of the charge carriers concentration profile across the sample. The concentration will become smaller in heated regions, while it will become higher in less heated ones. Moreover, the electric field can change its sign...

In semiconductors (but not in metals) all kinetic coefficients are strongly dependent on the extemal excitation. As a result, nonlinear effects due to heating of electrons by static and altemating electric fields (energy nonequilibrium), excess concentrations of electrons and holes under electric fields, photo-generation and gradient of temperature...

The equations of energy balance, heat balance, and diffusion heat balance are obtained for a bipolar semiconductor. The roles of nonequilibrium charge carriers and the recombina-tion in the heat transport are established. The expressions for the sources of energy fluxes, heat fluxes, and diffusion heat fluxes are discussed. Both radiative and nonra...

The equations of energy balance, heat balance, and diffusion heat balance are obtained for a bipolar semiconductor. The roles of nonequilibrium charge carriers and the recombina-tion in the heat transport are established. The expressions for the sources of energy fluxes, heat fluxes, and diffusion heat fluxes are discussed. Both radiative and nonra...

6° Congreso Internacional en lnnovacion y Desarrollo Tecnologico, 8al10 de octtJbre de 2008, Cuernavaca, Morelos., Mexico. Enfriamiento termoelectrico en peliculas delgadas. I. Lashkevych, 0. Angeles Fragoso, Yu, G. Gurevich Resumen: Las peculiaridades fisicas basicas de! fen6meno de enfriamiento termoelectrico en estructuras n-p con espesor de! or...

ECT2010

The perspective of use of radiatioa-stable semiconductor compounds with Ioose crystal structures for development of photovoltaic converters is discussed. Use of these semiconductors promises to get low cost solar ceIls witb extremely high radiation stability. A theoretical possibility of creation of photoconverters based on semiconductors of this t...

A general approach to the study of the energy exchange between hot electrons and phonons is presented. We present a discussion on the choice of the most suitable kinetic model to theoretically investigate the transport of both hot electrons and hot phonons. All of these kinetic models are based on the calculation of the symmetric part of the non-eq...

AbstracL A new approach to thermoelectric phenomena is presented, as a linear transport process of non-equilibrium charge carriers. Our study shows that the role of non-equilibrium carriers, as well as surface and bulk recombination, is crucial even within the linear approximation. General expressions for the thermoelectric current, thermo-e.m.f.,...

The perspective of use of radiation-stable semiconductor compounds with loose crystal structures for development of solid state devices is discussed. The theoretical possibility of creation of active electronic elements based on semiconductors of this type is shown. A feasible implementation of the solid-state amplifier on the basis of thin-film he...

A detailed analysis of the influence of thermal nonequilibrium on transport in semiconductors was carried out. It is shown that the transport of heat and electricity in bipolar semiconductors are interdependent and self-consistent. In a general case, the distribution of the temperature in homogeneous semiconductors cannot be constant or a linear fu...

Four possible cases of modelling a thermoelectric generator (TEG) are presented in this paper. Case 1 models equal hot and cold junction Seebeck coefficient (SC) ignoring Thomson effect (TE), case 2 adopts equal hot and cold junction SC including TE, case 3 defines unequal hot and cold junction SC neglecting TE while case 4 represents unequal hot a...

The review of Thomson heat is presented: the traditional and modern descriptions. It is emphasized that the value of Thomson heat in the newest and traditional descriptions are different. It is presented explanation that the Thomson heat is equal to the product of the Seebeck coefficient, the temperature gradient, and the current density. This is r...

Cubic GaN/GaAs (001) heterostructures were grown by RF-plasma assisted molecular beam epitaxy with different GaN nucleation temperatures. The heterostructures were studied by an open cell configuration of a photoacoustic experiment to obtain the effective thermal diffusivity (α) of the composite, which presented values varying from 14 to 28 mm 2 /s...

This article analyzes the behavior of electric charge carriers (electrons and holes) in a semiconductor material with metal contacts under thermodynamic equilibrium condition. Expressions were obtained for the concentrations of the electrons and holes, as well as for the Debye Radius () both in the general bipolar case, and in the particular cases...

A detailed analysis of the influence of thermal nonequilibrium on transport in semiconductors was carried out. Special attention was paid to the effect of this nonequilibrium on recombination and the space charge. In particular, recombination has the same mathematical expression for band-to-band and Shockley–Read–Hall transitions; the only differen...

A comprehensive study of the mechanisms of heating and cooling originating from an electrical current in semiconductor devices is reported. The variation in temperature associated with the Peltier effect is not related to the presence of heat sources and sinks if the heat flux is correctly determined. The Thomson effect is commonly regarded as a he...

Equations and boundary conditions for charge transport in a monopolar semiconductor of finite size with metal contacts are formulated. It is shown that metal–p-type semiconductor contacts are essentially different from those made with n-type semiconductors. Furthermore, it is shown that the bulk space charge established over distances on the order...

Ohm’s Law for a Bipolar Semiconductor: The Role of Carrier Concentration and Energy Nonequilibria

Talk

XVII International Forum on Thermoelectricity, Belfast, Great Britain, May 15--18, 2017, No. 13.

The theory of the nonequilibrium charge carrier transport in unipolar multivalley semiconductors is developed. It is shown that the diffusion of photoexcited nonequilibrium heavy and light electrons in multivalley semiconductors is a correlated process, like the ambipolar diffusion in the case of the electron-hole plasma. The light-induced interval...

The effective linear electrical conductivity of a nondegenerate bipolar semiconductor, sandwiched between two metals, is investigated taking into account both its nonequilibrium charge carriers (both electrons and holes) and nonequilibrium temperature. We stress that even in the linear perturbative approximation both carrier concentration and energ...

Thermoelectricity increasingly draws the attention of researchers because it can provide us with methods to generate environmentally clean energy and solid-state cooling. However, some problems in thermoelectricity’s physics remain unsolved. In this paper, a new approach to thermoelectric phenomena is presented, one that uses a linear description o...

It is known that when strong electric field is applied to a semiconductor sample, the current voltage characteristic deviates from the linear response. In this letter, we propose a new point of view of nonlinearity in semiconductors which is associated with the electron temperature dependence on the recombination rate. The heating of the charge car...

The functioning of the solar cells (and photoelectric phenomena in general) relies on the photo-generation of carriers in p–n junctions and their subsequent recombination in the quasi-neutral regions. A number of basic issues concerning the physics of the operation of solar cells still remain obscure. This paper reports on some unsolved basic probl...

Thermoelectricity increasingly draws the attention of researchers because itcan provide us with methods to generate environmentally clean energy and solid-statecooling. However, some problems in thermoelectricity’s physics remain unsolved. Inthis paper, a new approach to thermoelectric phenomena is presented, one that uses alinear description of th...

The interplay between physical origins of the nonequilibrium and their influence on the linear steady state transport processes in bipolar semiconductors are under investigation. Particular attention is paid to the influence of the energy nonequilibrium on the generation-recombination processes under various conditions. It is shown that in the case...

The peculiarities of the thermo-electric cooling phenomenon by an electric current are investigated for p-n thermally thick structures in a linear approximation. The possibility of the realization of an exotic distribution of the temperatures of electrons, holes, and phonons is demonstrated: the thermo-electric cooling takes place near the p-n inte...

It is shown that the transports of heat and electricity in bipolar semiconduc-tors are interdependent and self-consistent. Usually, the temperature is not a linear function of the coordinate, and in particular, not constant in a bipolar semiconductor in a stationary nonequilibrium state even in a linear approxi-mation with respect to a perturbation...

A general approach to study of energy interaction between hot electrons and phonons is presented. Basing on kinetic equations for both subsystems of these quasiparticles we suggest the most convenient models for the theoretical investigation of hot electrons as well as of hot phonons. All of these models are based on possibility of obtaining the sy...

A nonlinear model for the electric current in a metal-intrinsic semiconductor-metal structure without potential barriers in contacts is considered using a drift diffusion approach. An analytical solution of the continuity equations and the current-voltage characteristic for various recombination rates in the contacts are obtained. It is shown that...

The functioning of the solar cells (and photoelectric phenomena in general) relies on the photo-generation of carriers in p–n junctions and their subsequent recombination in the quasi-neutral regions. A number of basic issues concerning the physics of the operation of solar cells still remain obscure. This paper reports on some unsolved basic probl...

The functioning of the solar cells (and photoelectric phenomena in general) relies on the photo-generation of carriers in p–n junctions and their subsequent recombination in the quasi-neutral regions. A number of basic issues concerning the physics of the operation of solar cells still remain obscure. This paper reports on some unsolved basic probl...

The peculiarities of the thermo-electric cooling phenomenon by an electric current are investigated for p-n thermally thick structures in a linear approximation. The possibility of the realization of an exotic distribution of the temperatures of electrons, holes, and phonons is demonstrated: the thermo-electric cooling takes place near the p-n inte...

In this paper it is demonstrated that the precise physical nature of the Dember effect is a concentration gradient of nonequilibrium carriers under nonuniform illumination. We used the fact that any photo-EMF (electromotive force) can only exist in the presence of nonequilibrium charge car-riers, when there are two different Fermi quasilevels. That...