Open circuit voltage in homojunction and heterojunction silicon solar cells grown by VHF-PECVD

We present homojunction and muc-Si/a-Si:H/c-Si heterojunction silicon solar cells fabricated by PECVD. The H-2 dilution used during the i-layer growth strongly affects the device efficiency. While intermediate H-2 dilution of the gas mixture results in V-oc degradation, the best V-oc is obtained under zero or very high ( = 99.4%) H-2 dilution, resulting in totally amorphous or epitaxial i-layer respectively. A maximum value of 638 mV, with 13.7% efficiency, is observed in the case of an amorphous i-layer, indicating an improvement of interface quality. If the i-layer is deposited using a 99.4% H-2 dilution, a 608 mV V-oc is observed and for homojunction solar cells a 13.1% efficiency is obtained. (C) 2002 Elsevier Science B.V. All rights reserved.