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The photovoltaic performances of i-ZnO/CdS/Cu(In,Ga)Se2(CIGS) solar cell with different window architectures of SnO2:In2O3(ITO), Al2O3:ZnO (AZO) and ITO/AZO, were experimentally compared. The solar cell with ITO deposited directly on i-ZnO layer showed an abnormal current-voltage characteristic as having a shunt path. Both of AZO and ITO/AZO resulted in normal current-voltage behavior as far as AZO is contacting ZnO. [ABSTRACT FROM AUTHOR]

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]

In this study, in an effort to increase the surface Ga contents of Cu(In,Ga)Se2absorber, a high Ga-containing sputter target (Cu-30 at%Ga) was used to produce a precursor and was compared with Cu-22 at%Ga target in terms of photovoltaic performances of completed solar cells. The precursors consisted of multi-stack of CuGa/In and were selenized by using Se vapor at 530°C. The higher efficiency was obtained from the high Ga target with substantial improvement of open-circuit voltage and short-circuit current density. The increased hole concentration with more Ga addition in the absorber was found to be responsible for the higher open-circuit voltage. [ABSTRACT FROM AUTHOR]