Comparative Study of the Electrical Properties of CZTS-TiO2 and CZTS-ZnO Heterojunctions for PV Applications

Abstract

Two heterojunctions based on CU2ZnSnS4 were obtained as thin films, on FTO glass, by spray pyrolysis deposition. The choice of the n-type layer (TiO2 or ZnO) has impacted the nucleation and growth of the CZTS layers deposited on top. Crystalline thin films were obtained with drastically different morphologies. Small spherical grains promoted a better match at the interface between TiO2 and CZTS, while the hexagonal plates of ZnO promoted discontinuations. Both junctions proved photosensitive and gave good rectifying behavior but efficiencies lower than 0.01% suggest charge recombination at the interface or in the CZTS layer.