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

Single phase thin films of a layered oxysulfide, (La1-xSrxO)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,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. Sr2+ ion doping in the films was performed by adding SrS in the targets, which enhanced the p-type electrical conductivity from 6.4x10(-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. (C) 2002 Elsevier Science B.V. All rights reserved.