Toward stabilized 10% efficiency of large-area (>5000 cm2) a-Si/a-SiGe tandem solar cells using high-rate deposition

This paper reviews recent progress in large-area a-Si/a-SiGe tandem solar cells at Sanyo. Optimized hydrogen dilution conditions for high-rate deposition of hydrogenated amorphous silicon (a-Si:H) films and thinner i-layer structures have been systematically investigated for improving both the stabilized efficiency and the process throughput. As a result, a high photosensitivity of 106 for a-Si:H films has been maintained up to the deposition rate of 15 إ/s. Furthermore, the worldʹs highest initial conversion efficiency of 11.2% which corresponds to a stabilized efficiency of about 10% has been achieved for a 8252 cm2 a-Si/a-SiGe tandem solar cell by combining the optimized hydrogen dilution and other successful technologies.