Structural evolution optimization at p/i interface and in the bulk intrinsic‐layer for high efficiency microcrystalline silicon solar cells

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AbstractThe structural evolution in high‐rate deposited hydrogenated microcrystalline silicon (μc‐Si:H) films and solar cells has been investigated. In order to reduce the incubation layer thickness, a high‐quality initial seed layer at p/i interface has been developed by lowering silane concentration and very high frequency (VHF) power simultaneously. This initial seed layer not only acts as a seed layer for the high‐rate deposited i ‐layer, but also it can reduce the ion bombardment on the p/i interface. Then, a novel VHF power profiling technique, which is designed by dynamically decreasing the VHF power step by step during the deposition of μc‐Si:H, has been developed to control the structural evolution along the growth direction in the bulk i ‐layer. Another advantage of this VHF power profiling technique is the reduced ion bombardments on growth surface because of decreasing the VHF power. At last, a high conversion efficiency of 9.4% has been obtained for a single junction μc‐Si:H p‐i‐n solar cell with i ‐layer deposited at average deposition rate over 10 Å/s (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)