Effects of Cr doping in the structural and optoelectronic properties of Cu2ZnSnS4 (CZTS) thin film by magnetron co-sputtering

In this letter, we report the structural and optoelectronic properties of chromium-doped Cu2ZnSnS4 (CZTS:Cr) deposited by co-sputtering technique. Addition of chromium was observed to deteriorate the Cu2ZnSnS4 crystallinity as well as inducing the growth of cubic-ZnCr2S4 secondary phase. Grain size as large as 0.5 µm was observed for the doped sample. Bandgap was found to vary (1.51-1.70 eV), whereas the deep level defect state was calculated to be positioned at 0.20-0.33 eV above the valence band maximum (VBM) depending on the chromium concentration.