Zinc selenide films and heterojunctions

Abstract

Polycrystalline films of zinc selenide (ZnSe) have been deposited on glass and ZnO:F/glass substrates at 400–500 °C by the reaction of diethylzinc (DEZn) and diethylselenium (DESe) in a hydrogen atmosphere. The DESe/DEZn molar ratio in the reaction mixture is an important factor affecting the deposition rate and dopant incorporation in deposited films. The deposited films have high lateral electrical resistivity and poor photoconductivity. The resistivity can be reduced and photoconductivity significantly improved by the incorporation of a group VI (Cl or Br) or a group III (Al) dopant, and the use of trimethylaluminum (TMAl) as a dopant is considerably more effective than the use of Cl or Br compounds. The structural, optical, and electrical properties of ZnSe films have been characterized. The use of ZnSe films as a heterojunction partner in II-VI thin-film solar cells has been explored. Zinc telluride and cadmium telluride films were deposited on ZnSe/ZnO:F/glass substrates, and the characteristics of ZnSe/ZnTe and ZnSe/CdTe junctions studied.