Co-sputtered Cu2ZnTi(S:Se)4 absorbers for thin film solar cells

Abstract

Thin film solar cells are an exciting topic for low cost and high efficient solar cells. Owing to the high price of the indium metal in the fabrication of copper indium gallium diselenide (CIGS) solar cells, Cu2ZnSn(SSe)4 thin films are used as a new material to reduce the cost and increase the efficiency.As an alternative absorber material for solar cell production, Cu2ZnTi(S:Se)4 thin films were deposited by the co-sputtering method at various temperatures. During the deposition, Cu, ZnSe and Ti targets were used as metal sources. The Cu2ZnTi(S:Se)4 thin films were annealed in H2S:Ar (1:9) atmosphere. The morphological, structural and optical properties of Cu2ZnTi(S:Se)4 thin films was analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) Raman spectroscopy and UV–Vis–NIR spectrometer. It was seen that the thin films had good optical absorption till the infrared region and the band gap of the Cu2ZnTi(S:Se)4 thin films were smaller than the conventional Cu2ZnSnS4 thin films. Furthermore, fabrication of a solar cell with 1.96% power conversion efficiency was reported using a Cu2ZnTi(S:Se)4 thin film as a low cost absorber layer.