Multi-layered hydrogenated p-type microcrystalline silicon windows for a-Si:H thin film solar cells on opaque substrates

The effects of multi-layered p-type microcrystalline (mu c-) Si:H windows on the performance of substrate-type amorphous Si:H thin film solar cells on opaque substrates were investigated. The results were well explained in terms of H-2-plasma-induced damage (HPID) at the p/i-interface and the near-interface region of the light-absorbing layer. The mu c-Si:H was deposited using plasma enhanced chemical vapor deposition in a H-2-rich atmosphere. A high microcrystalline volume fraction was obtained with a high H-2 dilution ratio, which can cause considerable HPID. Cell efficiency was enhanced with a multi-layered p-type mu c-Si:H composed of films with low and high crystalline volume fraction, compared to cells with single-layered mu c-Si:H. In the multi-layered p-type mu c-Si:H, the low crystalline film was placed on an i-Si:H layer to reduce HPID. The present work demonstrated that HPID was reduced at the p/i-interface and the near-interface region of the light-absorbing layer, and that the quality of the p-type mu c-Si:H needs to be a significant consideration to achieve high efficiency. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.