Optimization of the longitudinal structure of intrinsic layer in microcrystalline silicon germanium solar cell

Abstract

Using radio-frequency plasma enhanced chemical vapor deposition, based on the influences of discharge power on structural and photoelectric properties of μc-SiGe:H thin films, RF power profiling technique is developed during the deposition of μc-SiGe:H intrinsic layer. The optimized μc-SiGe:H intrinsic layer not only maintains homogeneity of the crystalline volume fraction along the depth profile, but also forms a band gap profiling configuration from wide to narrow in the direction of growth. By this method, the fill factor and the short-circuit current density of μc-SiGe:H solar cell are significantly improved, and an efficiency of 9.54% for the a-Si:H/μc-SiGe:H tandem solar cell is achieved.