Photocurrent response of hydrogenated nanocrystalline silicon thin films

Abstract

We report on the optoelectronic properties of the hydrogenated nanocrystalline silicon (nc-Si:H) thin film containing large density of nanometer grains and voids. By comparison with the bulk silicon, strong optical absorption and high photocurrent are found in the nc-Si:H thin film and attributed to the enhancement of the optical absorption cross section and good carrier conductivity in the nanometer grains and voids. The observed strong photocurrent signals can be well described by the extended diffusion-recombination model. The high photocurrent response may facilitate the fabrication of infrared photodetector by a single layer of nc-Si:H thin film on a glass substrate, which shows superiority to the traditional amorphous Si photodetector with a diode or Schottky-barrier structure constructed by multilayer films on the crystalline Si substrate.