Study of CuS Thin Films for Solar Cell Applications Sputtered from Nanoparticles Synthesised by Hydrothermal Route

Abstract

Copper sulfide nanoparticles with a grain dimension between 10 nm and 50 nm were obtained by a simple chemical process in the first step. The reaction of thiourea with different sources of copper in distilled water, and by adjusting the proportion of reactants was studied. The synthesis of the nanoparticles was made by simple modified hydrothermal route at 90 °C for 2 hour followed by annealing at 500 °C for 1 hour using different types of Cu-precursors to obtain numerous compositions and structures of copper sulfide CuxS (Cu2S: chalcocite, Cu1.95S: djurleite and CuS: covellite) for a fixed copper sulphur molar ratio. These nanopowders, in second step, were grown onto glass substrates by RF magnetron sputtering technique at room temperature. The optical and structural properties of the films were investigated. The obtained CuS films with a thickness of about 300 nm were polycrystalline textured, preferentially oriented with the (101) crystallographic direction. From optical study the films present a band gap of about 2 eV. The obtained layers are promising for photovoltaic applications.