Current Photovoltaic Research ISSN:2288-3274(Print) 2508-125X(Online)

Cu₂ZnSnS₄ thin film have been fabricated by rapid thermal annealing of dc-sputtered metal precursor with Cu/ZnSn/Cu stack in sulfur ambient. A CZTS film with a good uniformity was formed at 560ºC in 6 min. Cu₂SnS₃ and Cu₃SnS₄ secondary phases were present at 540°C and a trace amount of Cu₂SnS₃ secondary phase was present at 560ºC. Single-phase large-grained CZTS film with rough surface was formed at 560ºC. Solar cell with best efficiency of 4.7% (V_oc = 632 mV, j_sc = 15.8 mA/cm², FF = 47.13%) for an area of 0.44cm² was obtained for the CZTS absorber grown at 560ºC for 6 min. The existence of second phase at lower-temperature annealing and rough surface at higher-temperature annealing caused the degradation of cell performance. Also poor back contact by void formation deteriorated cell performance. The fill factor was below 0.5; it should be increased by minimizing voids at the CZTS/Mo interface. Our results suggest that CZTS absorbers can be grown by rapid thermal annealing of metallic precursors in sulfur ambient for short process times ranging in minutes.