Studies on sulfur diffusion into Cu(In,Ga)Se2 thin films

A systematic study was carried out to investigate the distribution of sulfur (S) in CuInSe2 (CIS) and Cu(In,Ga)Se2 (CIGS) absorbers which were exposed to an H2S atmosphere at elevated temperature. Results demonstrated that S diffusion into CIS layers was a strong function of the original stoichiometry of the absorber before sulfurization. Sulfur inclusion into Cu-rich CIS films was much more favorable compared to S diffusion in Cu-poor layers. The sulfur distribution profile was also strongly influenced by the micro-structure of the original CIS and CIGS layers, with sections of the films with smaller grains accommodating more S. Copyright © 2000 John Wiley & Sons, Ltd.