In recent years, devices based on the Peltier effect, which is the basis for solid‐state thermoelectric cooling, have evolved rapidly to meet the fast‐growing electronic industry. The Peltier effect corresponds to the heat extraction or absorption occurring at the contact between two different conducting media when a direct current (DC) electric current flows through this contact. A comprehensive study of the mechanisms of heating and cooling originated by an electrical current in semiconductor devices is reported. The thermoelectric cooling in
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junction contacts, as well as inhomogeneous bulk semiconductors, are analyzed. Both degenerate and nondegenerate electron and hole gases are considered. The role of recombination and nonequilibrium charge carriers in the contact cooling (heating) effect is discussed. Along with the above, special attention is paid to several aspects of nonequilibrium thermodynamics of thermoelectric phenomena involved in Peltier effect in semiconductors that demand a careful examination. The formulation of an adequate self‐consistent theoretical model describing the Peltier effect is also presented.