In this study, we removed type II Sn-Se secondary phases from Cu2ZnSnSe4 (CZTSe) absorber surface via selective chemical etching and then examined the influence of this etching on the performances of solar cell devices. Experiment results indicate that the morphology of Sn-Se secondary phases are determined by the Ar gas flow rate (Sn/Se ratio) of the selenization process in the CZTSe absorber layer. Round or semicircular structures (type II) of Sn-Se secondary phases formed in films with a higher Ar gas flow rate (Sn/Se ratio) selenization process. We found that HNO3 with 3 HCl could remove type II Sn-Se secondary phases, thereby improving average device efficiency from 3.8% to 5.6%.
All Science Journal Classification (ASJC) codes
- Chemical Engineering (miscellaneous)
- Energy Engineering and Power Technology
- Materials Chemistry
- Electrical and Electronic Engineering