Fabrication of large area amorphous silicon/nanocrystalline silicon double junction solar cells

We have developed n-i-p type nc-Si:H solar cells using a large area RF plasma deposition at a rate of 3 angstrom/s. We have used the knowledge that ion bombardment and increasing temperatures cause defects in the nanocrystalline material. We therefore used higher pressures to reduce ion energy and lower temperatures to reduce defects. In order to maintain deposition uniformity over large areas at the higher pressures, we reduced the inter-electrode spacing (Paschen's Law). We have thus been able to obtain initial, aperture area (420cm(2)) efficiency of 11.8% with Ag/ZnO back reflectors. After laminating and light soaking these large cells, we obtained a stable, aperture area efficiency of 9.5%.