Thermoelectric properties of PbTe thin films prepared by gas evaporation method

PbTe thin films with fine grains were successfully fabricated by the gas evaporation method. Thermoelectric properties, i.e., Seebeck coefficient and electrical conductivity, both decreased with decreasing grain size. This was attributed to the decrease in carrier mobility exceeding the increase in carrier concentration with decreasing grain size. It was clarified that the effects of grain boundaries and of oxidation on carrier mobility are considerably large.