Enhanced Thermoelectric Properties of Cu2Se Flexible Thin Films by Optimizing Growth Temperature and Elemental Composition

As an emerging semiconductor, environmentally friendly thermoelectric material, Cu2Se has drawn great attention due to its outstanding thermoelectric performance. In this work, Cu2Se-based thin films were deposited on a flexible polyimide substrate by magnetron sputtering technique via in-situ growth method. The effect of growth temperature and Cu composition was investigated. The results indicate that the thin films grown at 200 °C have high electrical conductivity due to their high carrier mobility. Further adjusting of Cu composition can achieve highly (0l0)-preferred orientation Cu2Se-based thin films with optimized carrier concentration, resulting in an increase in Seebeck coefficient and further leading to the enhancement of power factor.