Optimisation of doped amorphous silicon layers applied toheterojunction solar cells
Abstract The optimisation of amorphous silicon layers (a-Si:H) is of key importance to obtain high efficiency heterojunction(HJ) solar cells. However since many mechanisms take place in photovoltaic energy conversion good electrical andoptical properties of a-Si:H films do not always result in high efficiency HJ devices. This is principally due to the useof very thin layers were interfaces are of capital importance and bulk properties are not always the main guideline tobest results on solar cells. In this work we focus on the doping analysis of (n) and (p) a-Si:H layers directly and theirimpact on solar cell results. First we have deposited and characterized simple (p) and (n) a-Si:H layers and then wehave integrated them on full heterojunction solar cells. We have correlated the solar cells characteristics (Jsc Voc andFF) with layer properties in order to understand the main mechanisms involved in the high performance of HJdevices. Finally we have chosen the best layers to improve the efficiency of our heterojunction solar cells on (n) c-Si125PSQ wafers up to 20% on an industrially-compatible process.