Influence of composition ratio on properties of Cu2ZnSnS4 thin films fabricated by co-evaporation

The influence of composition ratio on the properties of Cu2ZnSnS4 thin films fabricated by co-evaporation has been investigated. From the results of X-ray diffraction analyses, the full width at half maximum of the 112 diffraction peak becomes narrower with increasing Cu/(Zn + Sn) ratio, and the normalized intensity of the 112 diffraction peak becomes stronger with approaching stoichiometry. According to the scanning electron microscope observation, the grain size becomes larger with increasing Cu/(Zn + Sn) ratio, indicating the enhancement of the grain growth under Cu-rich growth condition. The electrical properties also depend on Cu/(Zn + Sn) and Zn/Sn ratios.