Study of hydrogenated a-SiGe cell for middle cell of Triple junction solar cell

Hydrogenated a-SiGe middle cell for triple junction solar cell was investigated with various process parameters. a-SiGe I-layer was deposited at substrate temperature 245?C and hydrogen content(R) was up to 26.7. Low optical bandgap(1.45eV) of a-SiGe cell was applied for middle cell although a-SiGe single cell efficiency with low Ge content was higher. And this cell was applied to the middle cell of a glass superstrate type a-Si/a-SiGe/uc-Si triple junction solar cell. The triple junction solar cell was resulted in the initial efficiency of about 9%, area 0.25cm², under global AM 1.5 illumination.