Preparation of Cu(In,Ga)Se 2 thin films from Cu–Se/In–Ga–Se precursors for high-efficiency solar cells

Abstract

Improved preparation process of a device quality Cu(In,Ga)Se 2 (CIGS) thin film was proposed for production of CIGS solar cells. In–Ga–Se layer were deposited on Mo-coated soda-lime glass, and then the layer was exposed to Cu and Se fluxes to form Cu–Se/In–Ga–Se precursor film at substrate temperature of over 200°C. The precursor film was annealed in Se flux at substrate temperature of over 500°C to obtain high-quality CIGS film. The solar cell with a MgF 2/ITO/ZnO/CdS/CIGS/Mo/glass structure showed an efficiency of 17.5% ( V oc=0.634 V, J sc=36.4 mA/cm 2, FF=0.756).