Photovoltaic characteristics of amorphous silicon solar cells using boron doped tetrahedral amorphous carbon films as p-type window materials

Boron doped tetrahedral amorphous carbon (ta-C:B) was prepared by filtered cathodic vacuum arc deposition. A band gap of 2.0eV and a conductivity of 1.42×10−7S∕cm were obtained at the doping ratio of 2.13at.%. A device structure was deduced from the conventional amorphous silicon (a-Si:H) solar cell using the ta-C:B window layer. Photovoltaic parameters of the cells were studied by varying the boron content in the ta-C:B films. A roughly 10% relative improvement of conversion efficiency was observed compared to the normal a-Si:H solar cell. The improved cell performance results from the enhancement of short wavelength response.