Amorphous and microcrystalline silicon based solar cells and modules on textured zinc oxide coated glass substrates

This paper addresses scientific and technological efforts to develop highly efficient silicon thin film solar modules on glass substrates. We present a comprehensive study of muc-Si:H p-i-n single junction and a-Si:H/muc-Si:H stacked solar cells prepared by plasma-enhanced chemical vapour deposition (PECVD) at 13.56 MHz excitation frequency. In the first step cell development was performed in a small area PECVD reactor showing, the relationship between deposition process and resulting solar cell performance. Subsequent up-scaling to a substrate area of 30x30 cm(2) confirmed the scalability to large area reactors. Moreover, we developed textured ZnO:Al films by sputtering and post deposition wet chemical etching as front contact TCO-material with excellent light scattering properties. A-Si:H/muc-Si:H tandem cells developed on this textured ZnO yielded stable efficiencies up to 11.2 % for a cell area of 1 cm(2). First solar modules were prepared in our recently installed process technology, which includes PECVD, sputtering, texture etching and laser scribing on substrate sizes up to 30x30 cm(2). Initial module efficiencies of 10.8 % and 10.1 % were achieved for aperture areas of 64 cm(2) and 676 cm(2), respectively.