A chemical bath process for depositing Cu 2 ZnSnS 4 photovoltaic absorbers

Thin films of Cu 2 ZnSnS 4 (CZTS) were fabricated through a combination of chemical bath deposition, ion exchange and sulfurization heat treatment. Scanning electron microscopy was used to study the morphology of the thin films, Auger electron spectroscopy for compositional analysis, X-ray diffraction and Raman scattering for structural characterization, and diffuse reflectance UV-Vis measurements for optical properties. With the method described, compositionally uniform microcrystalline CZTS with kesterite structure and a bandgap of 1.45 eV have been produced, and a preliminary solar cell device was fabricated to demonstrate that this material is applicable in earth-abundant, non-toxic thin film photovoltaics.