Effect of cu ratio on the growth of sprayed Cu2ZnSnS4 film

Abstract

We fabricated Cu2ZnSnS4 (CZTS) films by using the spray pyrolysis and the post-sulfurization methods. CZTS films were sprayed with different Cu-ratio precursors (Cu-ratio: 1.6, 2.0, 2.4) and substrate temperatures (Ts: 400, 430, 460 °C). In this substrate temperature ranges, the Curatio was found to have a more apparent effect on the growth of CZTS films than the substrate temperature. A higher Cu-ratio resulted in better crystallinity of the as-sprayed films, which was confirmed by using X-ray diffraction and Raman spectroscopy. In order to improve the crystallinity of the CZTS films, we carried out post-sulfurization, where the annealing temperature was increased to 568°C. After post-sulfurization, the crystallinity was improved for all CZTS films, which was also confirmed by using X-ray diffraction and Raman spectroscopy. CZTS films with higher Cu-ratios showed better crystallinity even in the post-sulfurized CZTS films.