Effects of Surface Morphology of Transparent Electrode on the Open-Circuit Voltage in a-Si:H Solar Cells

Abstract

The open-circuit voltage of hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells depends on the surface morphology of transparent electrodes and the i-layer thickness. We have studied the relationship between the V_oc and these parameters experimentally. To investigate the detailed mechanism of the V_oc drop, transmission and scanning electron microscopies (TEM and SEM) were used, and it was found by the TEM images that white stripelike defective regions were generated in the i-layer deposited on highly textured transparent electrodes. From the current-voltage characteristics of these solar cells under the dark condition, the relationship between the defects and the electrical properties of the cells has been studied. The results showed that the defect acts as a recombination center of carriers.