Preparation of Device-Quality Cu(In, Ga)Se₂ Thin Films Deposited by Coevaporation with Composition Monitor

Abstract

The chemical composition of Cu(In, Ga)Se 2 (CIGS) thin film was monitored in real time during the physical vapor deposition. The temperature of growing CIGS film was found to depend on the composition ratio of Cu/(In+Ga) when the film was deposited under constant heating power. The composition monitoring system can be easily applied to a 3-stage deposition process of the CIGS films. The solar cells (active area: 1 cm 2 ) fabricated by using the obtained CIGS absorber layer showed an efficiency of 15.4% under standard AM 1.5 illumination.