THERMOELECTRIC PROPERTIES OF SELENIDES AND TELLURIDES OF GROUPS VB AND VIB METALS AND THEIR SOLID SOLUTIONS

摘要

Tantalum substitutions at concentrations up to 5 at. ％ have been made in USe2, MoSe2 and MoTe2. Of these, p-type WSe2 doped with Ta had the best thermoelectric properties, with a. Figure of Merit of about 6.5 x 10-5 deg-1 from 500° to 1000°C. Substitution of a number of other elements was attempted in WSe2 and MoSe2, but only Group VB metals were sufficiently soluble to give materials with electrical conductivities at useful levels. Measurement of Hall coefficients on Ta-doped WSe2, MoSe2 and MoTe2 showed that the W compound had the highest carrier mobility, 100 cm2 v-1 sec-1. Measurement of Seebeck and Hall coefficients as functions of temperature, and carrier concentration indicated that WSe2 is a well-behaved semiconductor whose properties follow Boltzmann statistics.