Influence of Cd, S and Na atoms on photoluminescence in tin sulfide thin films

Abstract

The fundamental defects around the p–n interface were analyzed based on low temperature photoluminescence measurements to determine the origin of the various defects around the n-CdS/p-SnS structure in tin sulfide (SnS) solar cells. Particularly, the effects of Cd, S, and Na atoms on PL at the interface of a CdS layer and various treated SnS layers were examined. The PL peaks at 1.08 and 1.23 eV in the CdS/SnS structure, which were observed using the Cd partial electrolyte-treated SnS film, were associated with the formation of Cd-related defects. Furthermore, the PL peak at 1.27 eV in the CdS/SnS structure, which was observed using the sulfurized-SnS film and the excess Na-diffused SnS film, was associated with the formation of S-related defects such as OS defects. These findings present considerable potential for improving the efficiency of SnS solar cells.