Effect of cation ratios and monoethanolamine on the morphology of solution processed Cu ₂ ZnSnS ₄ films

Thin films of Cu2ZnSnS4 have been synthesized through solution chemistry. The correlation between film morphology and the ratio of cations (copper, zinc and tin) and the amount of monoethanolamine (MEA) in solution has been investigated. The stoichiometric ratio of cations resulted in films comprised of fine grains (∼165 nm) with large crystals (∼ 1-2μm) spread over its surface. The films corresponding to copper poor and zinc rich solutions were comprised of grains having uniform size (∼300 nm). The addition of MEA to precursor solutions resulted in a significant drop of pinholes in the films, however, at the same time grain size decreases to 50-200 nm range depending on the amount of MEA present in the precursor solution.