Phase transformation during Cu2ZnSnS4 synthesis by reactive magnetron co-sputtering

Abstract In this work we report on the relationship between the phase constitution and the chemical composition of Cu 2 ZnSnS 4 (CZTS) thin films synthesized by reactive magnetron co-sputtering of a zinc and a copper-tin alloy targets in reactive Ar–H 2 S atmospheres. In order to modify the film composition, the power applied to the alloy target was modified, while the other experimental parameters were kept constant. Based on previous works, the phase constitution of the films was determined by combining multi-wavelengths Raman spectroscopy and X-Ray diffraction analysis. In our experimental window, three sets of materials are grown. The main factor determining the phase constitution was identified to be the atomic sulfur concentration in the films. Indeed, an over-stoichiometry of sulfur ( +17 and 10 +20 . The CZTS like films present the highest carrier concentration which was explained by the presence of ZnS secondary phase. A relatively low Hall mobility was found, and explained by the small grain size (30–50 nm).