Electrochemical impedance analysis of spray deposited CZTS thin film: Effect of Se introduction

The present work deals with electrochemical impedance analysis of spray deposited Cu2ZnSnS4 (CZTS) thin films grown on fluorine doped tin oxide (FTO) substrates and effect of post Se introduction. The CZTS thin films are characterized using X-ray diffraction (XRD), X-Ray photo spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and UV-Vis spectroscopy techniques. The electrochemical measurements are carried out using impedance analysis spectroscopy. The strong peak in XRD pattern along (112) plane confirms the Kestrite crystal structure of CZTS film. The FE-SEM analysis reveals that nanoflakes contain crack-free surface microstructure changes with post Se introucation. The optical study reveals that absorption increases with Se dipping time and observed lower band gap of 1.31 eV. Introduction of Se in CZTS film results an improvement in the grain size and surface morphology which leads to increased electrical conductivity of CZTS film.