Copper tin sulfide semiconductor thin films produced by heating SnS―CuS layers deposited from chemical bath

摘要

Copper tin sulfide (Cu_4SnS_4) thin films have been prepared by heating a layer of CuS thin film deposited over an SnS thin film, both obtained by chemical bath deposition. Upon heating in a nitrogen atmosphere at 300―340℃, the CuS layer converts to Cu_8S_5, which reacts with the underlying SnS thin film at about 400℃ to form Cu_4SnS_4. The optical band gap of Cu_4SnS_4 has been found to be approximately 1 eV, involving direct forbidden transitions. The films are photosensitive, and the electrical conductivity in the dark is about 1 Ω~(-1) cm~(-1).