Characterization of Cu(In,Ga)Se2 Thin Film Solar Cells Fabricated by RF Magnetron Sputtering

Abstract

Thin film solar cells have been extensively investigated due to their small consumption of raw materials. Among them, Cu(In,Ga)Se2 (CIGS) solar cell has attracted great attention due to its merits such as direct band gap, high absorption coefficient, high conversion efficiency, and high radiation resistance, etc. CIGS thin films have been fabricated by using various deposition methods and the highest conversion efficiency of ~20% could be obtained by using CIGS thin films deposited by three-stage co-evaporation method. However, this method may not be applicable to mass production of large area CIGS solar cells because the process is not simple and delicate process control is needed. Sputtering method has been widely used for fabricating large area thin films. In this work, CIGS thin films were deposited on Mo/glass substrates at various substrate temperatures by using rf magnetron sputtering. For simplicity, a single CIGS target was used. Composition and structural, optical properties of the CIGS thin films were investigated by using EPMA, XRD, SEM, spectrophotometer, and photoluminescence, etc. and Al/AZO/i-ZnO/CdS /CIGS/Mo/glass structure was fabricated to measure the conversion efficiency. Detailed results will be presented for a discussion.