The stability of MIS solar cells and evaluation by C-V characteristics

To test the stability of MIS solar cell structures, we investigated the I-V and C-V characteristics during tests under illumination and dark conditions. The MIS solar cells were prepared using two different techniques to produce two types of oxide layer. Under illumination, the tested devices suffer from degradation. The rate of degradation was higher for cells with a thinner oxide layer. The cells with a thicker oxide layer exhibited a partial recovery for the open circuit voltage after storage in the dark. The degradation is due to the photo-neutralization of effective charges at the oxide-semiconductor interface, This mechanism leads to instability in the cell performance through changes in the barrier height. The C-V measurement confirms this result. (C) 2001 Elsevier Science Ltd. All rights reserved.