Critical Assessment of Sub-Bandgap Primary Photocurrent in a-Si:H Based Solar Cells.

The sub-bandgap primary photocurrent and the solar cell performance of a-Si:H p-i-n devices have been studied before and after light induced degradation. The results indicate significant discrepancy between the two methods when used to estimate the degree of degradation and the defect density in the i-layers. A preliminary explanation is proposed.