Influence of the Precursor Annealing on the Cu(In,Ga)Se 2 Solar Cell Performance.

The stacked CuGa/In metallic precursor thin films were fabricated and annealed at low temperature of 200°C before the selenization for fabricating Cu(In,Ga)Se2photovoltaic absorber. The pre-annealing of Cu-In-Ga precursor was found to reduce Cu9Ga4phase and increase the formation of Cu16(In,Ga)9phase, which may be preferable for the subsequent selenization in terms of homogenizing Ga across the absorber thickness. However, the replacement of In with Ga in the ternary phase produced large amount of free-In, which gave rise to blistered area as shunt paths after the selenization. The performance of solar cell fabricated using the pre-annealed precursor was heavily deteriorated compared to the not-annealed precursor. [ABSTRACT FROM AUTHOR]