Abstract
In this study, the microstructure of the CVD-fabricated Cu(In,Ga)Se2 (CIGSe) absorber layer by simulating the stacking sequence used in a co-evaporation method, and changes solar cell performance were investigated. The absorber layer prepared by stacking CuSe and (In,Ga)Se between InSe is separated into Ga-free CuInSe2 and Ga-rich CIGSe, and transformed to CIGSe by selenization heat treatment with slight improvement in the the solar cell efficiency. However, in CVD, since the supply of liquid Cu-Se is not as active as in the co-evaporation method, the nanoocrystalline layer containing a large amount of Ga remained independently in the absorption layer, which acted as a cause of the loss of JSC and FF. Therefore, by using a precursor structure in which CuGa is sputter-deposited on a single layer of InSe deposited by CVD, performance parameters of VOC, JSC, and FF could be greatly improved.