Taking account of continuously distributed gap states and a considerably small carrier mobility inherent to amorphous material, a unique photovoltaic behavior in an amorphous silicon has been examined in a p-i-n junction structure. Geminate and non-geminate recombination would play a significant role in the photo-carrier generation and photovoltaic carrier collection process, respectively. It has been shown that in the case of a properly designed a-Si:H p-i-n junction photovoltaic cell the carrier collection loss can be almost saved with the aid of high internal electric field in the i-layer despite of a very small hole diffusion length of about 500Å. While, owing to the geminate recombination, as high as 20% of absorbed photons are still thrown away without being converted to photocurrent.