EFFECT OF THE SELENIUM CONTENT IN THE OPTICAL PROPERTIES OF THE KESTERITE Cu2ZnSnS4-xSe x PHASES

Abstract

Polycrystalline Cu 2 ZnSnS 4-X Se X (X=1, 2, 3) compounds were synthesized by conventional solid-state reactions. The samples were characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray analysis (SEM-EDS), Raman spectroscopy, diffuse reflectance UV-vis and Photoluminescence. All of phases crystallize in the tetragonal kesterite-type structure. The powder X-ray diffraction (XRD) patterns were indexed in the space group . No secondary phases were detected in XRD patterns. The results from diffuse reflectance show band gap between 1.26 -1.17 eV, when S is gradually replaced by Se. The PL spectrum of Cu 2 ZnSnS 4-x Se x phases shows nearly symmetrical band, which shifted linearly to the lower energy with increasing Se content. The selenized (CZTSSe) phases are promising candidates to be used as absorbing material in solar cells