A simple chemical approach for the deposition of Cu2ZnSnS4 thin films

The direct synthesis of Cu2ZnSnS4 (CZTS) on substrates by wet‐chemistry methods is of great interest for the fabrication photovoltaic thin‐film solar cells. We report a simple chemical bath deposition approach to form CZTS thin films on SLG glass substrates. CZTS films were directly deposited onto glass substrate at 60 °C using copper sulfate, zinc sulfate heptahydrate, tin sulfate dihydrate, and sodium thiosulfate as precipitating agents. Deposition of individual metal sulfide (Cu2S, ZnS, and SnS2) showed homogeneous‐reaction dominant nanostructures rather than continuous thin film. By contrast, the combination of two or three metal precursors formed continuous thin films. As‐grown CZTS films deposited with both NH3 and TEA showed a kesterite CZTS crystal structure. However, the absence of either NH3 or TEA caused no crystallized CZTS film formation. The as‐grown CZTS films showed a kesterite crystal structure. Optical absorption study indicated that the as‐grown CZTS films had the optimum bang gap energy of 1.6 eV.