Annealing effects of the untreated and sulfur-treated electrodeposited n-type and p-type cuprous oxide thin films

Abstract

The n-type and p-type cuprous oxide thin films were electrodeposited potentiostatically in acetate and lactate baths, respectively. Sulfur treatment of n-type and p-type cuprous oxide surfaces were achieved using gaseous (NH4)2S. Sulfur treated Cu2O films were annealed in air at 100, 150, 200, 250, 350, and 450 8C for unique times to obtain the best photocurrent. Unannealed and annealed samples of sulfur treated and untreated cuprous oxide were then investigated using high-energy X-ray diffraction (HEXRD). The HEXRD measurements and the pair distribution function (PDF) analysis revealed that the sulfur treatment leads to the formation of crystalline CuS on Cu2O film surfaces. The present study also shows that the sulfur treatment causes minor structural changes in Cu2O samples due to the formation of CuS. It was observed that the sulfur-treated cuprous oxide samples retarded the formation of CuO at higher temperatures showing good thermal stability and enhancement of the photoactivity of the n-type and p-type cuprous oxides