Relationship between the photo-induced degradation characteristics and film structure of a-Si:H films prepared under various conditions

We have investigated the photo-induced degradation characteristics of high growth-rate (~20 Å/s) a-Si:H films prepared under various conditions and find that the stability of the film is closely related to the Si-H₂ bond density in the film. The results obtained by the Schottky cell measurements indicate that highly stable films with low Si-H₂ bond density are obtained at moderately high temperatures of around 350°C. As our first trial, we made a small number of nip solar cells at high growth-rate (~20 A/s) and confirmed the consistency between the result of the Schottky cell behavior and the solar cell performance. The best performance cell we have obtained so far exhibits a 9.3% initial efficiency, with a stabilized efficiency of 7.4% after a 500 h, AM1.5, 100 mW/cm² light exposure