Efficient $CuInS2$ solar cells by reactive magnetron sputtering

We demonstrate $CuInS2$ thin film solar cell device efficiencies larger than 10% by preparing the absorber layers by reactive magnetron sputtering from metallic targets in an argon-hydrogen sulfide atmosphere. At deposition temperatures below $500°C$ the polycrystalline films show a compact morphology with grain sizes of several micrometers. Solar cell devices show optical and electrical properties that are comparable to coevaporated or sequentially processed cells, in particular, diffusion lengths larger than $2μm$ and fill factors larger than 70%. We conclude that ion bombardment during the sputtering process does not lead to a significant increase of electronically active defects in these devices.