The phase optimization, optical and electrical properties of kesterite Cu2ZnSnS4 thin film prepared by single target RF magnetron sputtering technique for solar cell application

Abstract

Cu2ZnSnS4 (CZTS) thin film was prepared by RF sputtering technique from a single quaternary target by optimizing RF power, in situ substrate temperature and post deposition annealing temperature. The single phase formation of crystalline CZTS thin film has been verified at a particular optimized condition by characterizing through x-ray diffraction, Raman spectrometer and x-ray photoelectron spectroscopy. The kesterite structure has been further confirmed from the lattice fringes of high resolution transmission electron microscope and selected area electron diffraction study. The surface properties such as particle size, shape and roughness and elemental composition of amorphous and crystalline phase of CZTS studied by atomic force microscope, scanning electron microscope and energy dispersive analysis of x-rays. The optical absorption and photoluminescence studies of post-deposition annealed film prove the defect free and single phase CZTS formation. The band gap calculation for crystalline CZTS showed band gap of 1.49 eV calculated from the Tauc plot. The electrical properties of optimized CZTS thin film has been studied from Hall effect measurement showing P-type conductivity with better carrier concentration and Hall mobility.