Abstract
In the present work, Cu2ZnSnS4 (CZTS) thin films were deposited by spray pyrolysis, the effect of zinc molarity on films structural, optical and electrical properties was investigated. CZTS films were grown by pneumatic spray pyrolysis with various zinc salt molarities. The structural properties reveal that all prepared CZTS films have a kesterite structure with a preferential orientation along (112) plan with the presence of secondary phases. Film composition and structural property vary with Zn molarity: at relatively low Zn molarity CuS secondary phase is formed, while with increasing Zn molarity ZnS secondary phase is formed. The crystallite size increases from 25 to 125 nm with increasing Zn molarity. Films transmission spectra show low transmission in the visible range, whereas the band gaps varies slightly with Zn salt molarity, it lies between 1.3 and 1.37 eV. Hall Effect measurements were employed to determine the electrical properties of CZTS films. The films conductivity is a p type, it is reduced with increasing Zn molarity due to the reduction of free carriers concentration caused by carriers loss at ZnS/CZTS interface and the presence of the resistive ZnS phase.