Thermal Field—The Source of the Emergence of Nonequilibrium Charge Carriers in Semiconductors

The new point of view of thermoelectric phenomena as a transport process of nonequilibrium charge carriers is presented. It is shown that Fermi quasilevels, which characterize transport in a system far from equilibrium can be nonmonotonic functions of the spatial coordinates. The role of recombination in affecting the thermoelectric phenomena is discussed for the first time. It is shown that in the presence of thermal fields there appears a new term in the expression for recombination which depends on the inhomogeneity of temperature. If electron and hole temperatures are different, which is a typical case in semiconductors, there appears one more new term in the expression for recombination which is proportional to the difference of electron and hole temperatures. A new method for the characterization of semiconductor materials connected with measurement of thermopower is proposed. It is shown that nonstationary thermal fields are most appropriate for this purpose.