Optimisation of the Thermoelectric Figure of Merit in Fine Grained Semiconductor Materials Based upon Lead Telluride.

摘要

This report although referred to as final, actually covers progress made during the period January to March 1984. The next step in this investigation was the development of a theoretical model which would enable a realistic estimate to be made of the absolute magnitude of the thermoelectric figure of merit Z of materials based upon lead telluride. In report No 4 we reported the results of a preliminary investigation into the effect of including a multivallied energy band structure in our model; this was an essential step as all established thermoelectric materials, including those based upon lead telluride possess such an energy band structure. In addition to possessing a multivallied energy band structure, materials based upon lead telluride have narrow energy band gaps. Narrow gap semiconductors in general possess non-parabolic energy surfaces and the difficulties encountered in obtaining a satisfactory agreement between theory and experimental data bas been resolved by including non-parabolicity in our theoretical model.