Effect of selenization on local current and surface potential of sputtered Cu2ZnSn(S, Se)4 thin-films with 8% conversion efficiency

Cu₂ZnSn(S, Se)₄ (CZTSSe) is emerged as a promising material because of non-toxic, inexpensive and earth abundant more than Cu(In, Ga)Se₂. The highest conversion efficiency of CZTSSe is 11.1 % at IBM based on hydrazine process [1]. We have achieved CZTSSe thin-film solar cell 8% conversion efficiency by sputtering process. CZTSSe thin-films show different efficiency depending on selenization process. Depending on the different selenization process, conversion efficiencies in each sample are definitely distinguished from 8.06 to 3.17%. We investigated local electrical properties on these samples. The local surface potential is also critically different, which is ~ 200 mV on 8.06% film and ~ 70 mV on 3.17% film. From these results, we can suggest that selenization process can affect to local electrical characteristic as well as improving solar cell performances.