The influence of heat treatments on the thermoelectric properties of copper selenide thin films prepared by ion beam sputtering deposition.

In this study, copper selenide thin films were fabricated by ion beam sputtering deposition by using a fan-shaped target of Cu and Se. The influence of heat treatment on thermoelectric properties of copper selenide thin films was investigated. X-ray diffraction results demonstrate that the as-deposited and annealed thin films are both amorphous. The SEM images show that the thin films are discontinuous and just like island structure. The thin films are crystalline when the substrate temperature is added at the deposition process. The thin film exhibits the dominating CuSe phase at the substrate temperature of 250 °C and it transforms to single CuSe 2 phase at the temperature of 300 °C. When the substrate temperature further increased to 350 °C, the mixed Cu 2−x Se phase is dominated. The thin film with Cu 2−x Se phase has a high electrical conductivity of 2.02 × 10 4 Scm −1 at 423 K and thin film with CuSe 2 phase has a high Seebeck coefficient of 37.3 μVK −1 at 316 K. [ABSTRACT FROM AUTHOR]