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Abstract: The electrical characteristics of Cu(In,Ga)Se2-based solar cells with In2S3 buffer were investigated. The effects of post-deposition annealing in helium or in air on current–voltage characteristics, net acceptor density profiles and admittance spectra were studied. Analysis of the current–voltage characteristics showed that interface recombination dominated transport in the as-deposited devices was reduced after annealing and partially replaced by bulk recombination. This was accompanied by a decrease in the saturation current and diode ideality factor. The influence of the heat treatment on the buffer/hetero-interface region as determined by capacitance measurements was minor. We conclude that a reduction in the interface states density and in the p+ layer doping caused by the chemical modification of the hetero-interface region is the major source of the improvement. [Copyright &y& Elsevier]

Compound In 2 S 3 powder was evaporated on Cu(In,Ga)Se 2 substrates from the ZSW inline multi-stage co-evaporation process. Laboratory devices with the complete layer structure Mo/CIGS/In 2 S x /i-ZnO/ZnO:Al/Ni–Al grid on 0.5 cm 2 total cell area were prepared and analysed for their J–V characteristics. A post-annealing step in air after completing the device is essential to enhance the cell performance. In this work the influence of window process conditions like process temperature, layer thickness and sputtering gas composition on the cell characteristics was investigated. Electrical characterisation by temperature-dependent current voltage and admittance spectroscopy were performed to better understand the impact of buffer parameters on electrical transport. By optimization of the buffer layer thickness in combination with window layer variations, cell efficiencies >16% could be achieved. A record cell efficiency of 18.2% with anti-reflective coating was obtained. [ABSTRACT FROM AUTHOR]