Properties of high-efficiency CuInGaSe2 thin film solar cells

In this paper, we present recent results on the growth and characterization of CuInGaSe2 (CIGS) thin film solar cells by the three-stage process. A conversion efficiency of 19.3% and 18.4% has been achieved for solar cells made from absorbers with band gap values of 1.15 and 1.21 eV, respectively. High open circuit voltages and fill factors are obtained. We attempt to relate these improvements to material and device properties. The results suggest that it might be possible to produce a 20% efficient solar cell by further optimization of the current collection.