Absence of carrier recombination associated with the defect pool model in intrinsic amorphous silicon layers:: Evidence from current-voltage characteristics on p-i-n and n-i-p solar cells

Forward bias current-voltage characteristics (J(D)-V) were studied for both p-i-n (superstrate) and n-i-p (substrate) (a-SiC:H p)/(a-Si:H i) solar-cell structures having different p/i interface layers and different thickness i-layers. Contributions of the p/i interfaces to the J(D)-V characteristics were separated, and the dependence on the thickness of the i-layers was established. Equivalence was observed in a comparison of the characteristics of p-i-n and n-i-p cells. The various J(D)-V characteristics are found to be consistent with uniform densities of defects in the i-layers, and thus inconsistent with the spatially varying large densities of defects predicted for solar-cell structures by the defect pool model. (C) 2003 American Institute of Physics.