Influence of Laser Incident Energy on Chemical Composition, Crystal Structure, Morphology and Band Gap of Cu2ZnSnS4 Thin Films by Pulsed Laser Deposition

Abstract

Abstract. The Cu 2 ZnSnS 4 (CZTS) thin films were successfully prepared on glass substrate by pulsed laser deposition (PLD) using CZTS target. The laser incident energy was varied from 3 J·cm -2 to 6 J·cm -2 at the interval of 1 J·cm -2 , and its influence on chemical composition, crystal structure, morphology and band gap of CZTS thin films was investigated by energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet-visible-near infrared (UV-Vis-NIR) absorption spectra, respectively. The result of EDS indicated that these CZTS thin films were Cu-rich and S-poor. The XRD study showed CZTS thin films exhibited strong preferential orientation of grains along [112] direction. The band gap of CZTS thin films was 1.72, 1.37, 1.25 and 1.11 eV corresponding to incident laser energy of 3, 4, 5 and 6 J·cm -2 . IntroductionCu 2 , and pulsed laser deposition (PLD) [11][12][13]. The solid-state reaction of the mixing powder of Cu 2 S, ZnS, and SnS 2 with 1:1:1 mol ratio was used to prepare the target in PLD, and the target directly using the CZTS nanocrystal was not reported.In this paper, the CZTS thin films were prepared on glass substrate at the substrate temperature of 400℃ using the target from the CZTS nanocrystal. The influence of laser incident energy on chemical composition, crystal structure, surface morphology and band gap of CZTS thin film was systemically investigated by energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet-visible-near infrared (UV-Vis-NIR) absorption spectra, respectively.