Effect of real working environment/formation of oxide phase on thermoelectric properties of flexible Sb2Te3 films

Abstract Flexible Sb 2 Te 3 thin films, for thermoelectric generator applications, were deposited by DC magnetron sputtering. As-deposited films were annealed in air to simulated a realistic operating environment. The oxidation behavior of the films was studied by monitoring their phase change on exposure to air at different temperatures between 50 and 300 °C for annealing times from 1 to 15 h. Oxidation of Sb and Te formed Sb 2 Te 4 and TeO 2 phases when annealing above 100 °C and Sb 2 Te 3 decomposed into oxide phases at an annealing temperature of 250 °C for 15 h. The thermoelectric performance decreased as the content of Sb 2 O 4 and TeO 2 phases increased. These findings show the limitations of Sb 2 Te 3 films operating in air without vacuum or a protective environment. We propose that the kinetic growth of oxide formation on the Sb 2 Te 3 thin films depend on chemical activation energy and oxygen diffusion through the oxide barrier by the variation of annealing temperature and annealing time, respectively.