Preparation of high quality a-SiGe:H films and its application to the high efficiency triple-junction amorphous solar cells

The optical and electrical properties of a-SiGe:H films with optical gaps of 1.45-1.55 eV were evaluated and the corresponding solar cell performances were compared. Taking into account the influence of Ge and hydrogen content, the deposition conditions were chosen so as to obtain films with high ratios of photoconductivity to dark conductivity. An enhancement in the spectral response of a-SiGe:H p-i-n cells at long wavelengths was obtained as a result of an improvement in film quality and the utilization of a black reflector. High-efficiency triple-junction solar cells using the a-SiGe:H p-i-n cells as bottom cells were fabricated to achieve 9.5% efficiency for a cell size of 100 cm/sup 2/.<
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