ABSTRACT
We recognize that energy can exist in different forms like electrical energy, thermal energy, mechanical energy, chemical energy, nuclear energy, etc. Among these, electrical energy has been recognized as the one which can be easily used or converted into other forms of energy. Hence, a large number of electrical energy generators have been developed which convert various forms of energy into electrical energy like chemical to electrical, nuclear to electrical, optical to electrical thermal to electrical, mechanical to electrical energy converters, and the like. In the thermal to electrical energy converters, i.e., thermoelectric generators, for the efficient conversion of heat energy into electrical energy, a knowledge of material transport properties like thermoelectric power, electrical conduction and thermal conduction in the material is very important. As these parameters are not independent but depend on one another, a quantity defined as the "figure of merit" involving all these three parameters is generally used to evaluate the suitability of a particular material, i.e., its merit for application to thermoelectric generation. Of course, the thermoelectric power of the material is the first important parameter whose knowledge is required. When the "merit" of a material is examined, we find that only a very few semiconducting materials satisfy the requirement.
