Carrier collection losses in amorphous silicon and amorphous silicon–germanium alloy solar cells

Abstract
The carrier collection losses in amorphous silicon (a-Si) and amorphous silicon–germanium (a-SiGe) alloy single-junction nip cells have been experimentally investigated by measuring the biased quantum efficiency and color (blue and red) fill factor values. The study has identified losses near the p/i junction and the bulk of the i layer. The extent of the losses have been found to be dependent on the quality and thickness of the i layer and the nature of the n-layer surface. The results suggest a broad interrelationship between the initial film properties and deposition conditions and an inhomogeneity in the direction of film growth.