Amorphous silicon/crystalline silicon heterojunctions for solar cells

Amorphous silicon/crystalline silicon (c-Si) heterojunctions are studied by contactless transient photoconductivity measurements at the microwave frequency range. Excellent passivation of the n-type crystalline silicon (n c-Si) surface by n-type, hydrogenated amorphous silicon (n a-Si:H) films is observed. The influence of band offsets is discussed. It is shown that energy converting junctions can be characterized accurately by these measurements. Charge carrier kinetics in the junctions are controlled by charge carrier separation determined by band bending and by interface recombination.