Drastic increase in thermoelectric power factor of mixed Sb2Te3-In2Te3 thin films

Abstract

Thermoelectric power factor is an indicator of the performance of a thermoelectric material. Attempts have been made by various techniques, like doping, to improve the thermoelectric conversion efficiency of materials. In the present study, a layer structured thermoelectric material Sb<inf>2</inf>Te<inf>3</inf> is alloyed to In<inf>2</inf>Te<inf>3</inf> using vacuum deposition method at 423 K to significantly enhance the power factor of ?118 ?Wm-1K?2 (at 450 K). Structurally, all films were polycrystalline in nature as clearly reflected in XRD patterns. All films were showing p-type conductivity, and electrical conductivity of In<inf>2</inf>Te<inf>3</inf> films increased with increasing Sb<inf>2</inf>Te<inf>3</inf> content. The seebeck coefficient is found to be higher for un-doped In<inf>2</inf>Te<inf>3</inf> than that of Sb<inf>2</inf>Te<inf>3</inf>-In<inf>2</inf>Te<inf>3</inf> and pure Sb<inf>2</inf>Te<inf>3</inf> films. However, the thermoelectric power factor of 25% Sb<inf>2</inf>Te<inf>3</inf> alloyed In<inf>2</inf>Te<inf>3</inf> films is enhanced by 11.9 times that of In<inf>2</inf>Te<inf>3</inf> films and 4 times that of Sb<inf>2</inf>Te<inf>3</inf> films at 320 K. It is interesting to note that efficiency of the mixed films is higher than that of the individual films. © 2019 Elsevier Ltd