Preparation of transparent p-type (La1−xSrxO)CuS thin films by r.f. sputtering technique

Abstract Single phase thin films of a layered oxysulfide, (La 1− x Sr x O)CuS ( x =0, and 0.03), were prepared by r.f. sputtering technique followed by a post-annealing treatment in an evacuated silica tube containing a small amount of (LaO)CuS powder. Key growth parameters for obtaining a single-phase film were the r.f. power and the substrate temperature in r.f. sputtering under an H 2 S atmosphere. ICP and FP-XRF measurements revealed that the chemical compositions of post-annealed films prepared under optimum conditions were in significant agreement with those of the target. Sr 2+ ion doping in the films was performed by adding SrS in the targets, which enhanced the p-type electrical conductivity from 6.4×10 −5 ( x =0) to 20 S cm −1 ( x =0.03). Optical transmission spectra of the films showed high optical transmission (>60%) in the visible–near IR region.