Peltier effect in a co-evaporated Sb2Te3(P)-Bi2Te3(N) thin film thermocouple

Abstract A thin film Sb2Te3-Bi2Te3 based thermocouple was fabricated by co-evaporation. The conditions for deposition have been investigated as a function of substrate temperature (Ts) and flux ratio [Fr=F(Te)/F(Sb,Bi)] and optimised to achieve a high thermoelectric power factor. It has been observed that the Seebeck coefficient and electrical conductivity of p-type Sb2Te3 thin films (αp, ρp) and n-type Bi2Te3 thin films (αn, ρn) deposited by co-evaporation were found to be approximately 160 μV/K, 3.12×10−3 Ωcm and −200 μV/K, 1.29×10−3 Ωcm, respectively. From optimal deposition parameters, a thin film thermocouple was fabricated and operated in Peltier mode. The observed maximum value for temperature difference between hot and cold end is approximately 15.5 K for a current of 55 mA. The figure of merit and coefficient of performance of the thermocouple are estimated.