Vapor deposition of copper(I) bromide films via a two-step conversion process

Thin films of Cu2S grown by pulsed-chemical vapor deposition of bis(N,N′-di-sec-butylacetamidinato)dicopper(I) and hydrogen sulfide were converted to CuBr upon exposure to anhydrous hydrogen bromide. X-ray diffraction shows that the as-deposited films have a polycrystalline Cu2S structure. After exposure to HBr gas, the surface of the films is transformed to a γ-CuBr polycrystalline structure. Scanning electron microscopy and X-ray photoelectron spectroscopy reveal complete conversion of up to 100 nm of film. However, when the conversion to CuBr approaches the interface between as-deposited Cu2S and the SiO2 substrate, the morphology of the film changes from continuous and nanocrystalline to sparse and microcrystalline.