Regulation of Zn/Sn ratio in kesterite absorbers to boost 10% efficiency of Cu2ZnSn(S, Se)4 solar cells
Min Xue1, 2, Shi Jiangjian1, 2, Guo Linbao1, 2, Yu Qing1, 2, Zhang Pengpeng1, 2, Tian Qingwen3, Li Dongmei1, 2, Luo Yanhong1, 2, Wu Huijue1, 2, Meng Qingbo1, 2, †, Wu Sixin3, ‡
       

(color online) (a) Normalized Raman spectra for R0–R4 CZTSSe absorber films. (b) Zoomed-in Raman spectra at the wave number from 220 cm−1 to 280 cm−1.