A role of a-Si:H buffer layer for controlling the impurity profiles near p/i interface of microcrystalline silicon solar cell

The application of a high-quality hydrogenated amorphous silicon (a-Si:H) buffer layer to a hydrogenated microcrystalline silicon (/spl mu/c-Si:H) solar cell was investigated. It was revealed that /spl mu/c-Si:H solar cells with and without the buffer layer showed different profiles for impurities in the active layer, especially near the p/i interface. The efficiency of the /spl mu/c-Si:H solar cells with the a-Si:H buffer layer was completely stable during light irradiation, while the solar cell without the buffer layer showed small variations in efficiency. These results suggests that an a-Si:H buffer layer is effective for the suppression of the amount of impurities in the active layer, especially near the p/i interface, and also for suppressing variations in the output properties of the /spl mu/c-Si:H solar cell. Based on the results, a conversion efficiency of 9.33% was obtained for a /spl mu/c-Si:H solar cell that showed no variation in efficiency.