Photocurrent of hydrogenated nanocrystalline silicon thin film/crystalline silicon heterostructure

Abstract

We report on the photocurrent properties of the hydrogenated nanocrystalline silicon (nc-Si:H) thin film/crystalline silicon (c-Si) n-p heterostructure. By comparison with the c-Si n-p homojunction, two Gaussian-type photocurrent peaks are observed in the nc-Si:H/c-Si heterostructure and attributed to be transitions from a tail band or discrete levels in quantum dots with localized states, and a miniband with extended states associated with the embedded nanometer crystallites in the amorphous boundaries of the nc-Si:H thin film. The observed strong photocurrent signals and temperature dependency have revealed the unique electronic states of the miniband in the nc-Si:H thin film. Our investigations into the photocurrent properties may help to realize nc-Si:H/c-Si heterostructure-based optoelectronic devices.