Photovoltaic properties of boron-doped amorphous carbon on n-Si with C/sub 60/ intermediate layer deposited by rf nitrogen plasma co-sputtering of graphite and boron

Photovoltaic cells based on boron-doped amorphous carbon on n-Si with C/sub 60/ intermediate thin layer between them have deposited by rf nitrogen plasma co-sputtering of graphite and boron targets in a UHV chamber. In order to identify the effect of rf input power of graphite sputtering, the rf power was varied between 15 W and 100 W by keeping that of boron was constant at 300 W. A p-type a-C/C/sub 60//n-Si heterojunction solar cells with conversion efficiency as high as 0.00015% have been fabricated. The spectral response of cell photocurrents in the short wavelength region below 400 nm and 700 nm are determined to be due to the optical absorption of the boron-doped a-C and C/sub 60/ layers, respectively, based on the absorption peaks measured by UV-visible spectroscopy. The photovoltaic properties of the a-C based solar cell structures are discussed with the dark and illuminated current density-voltage characteristics as well as optical properties of boron-doped a-C film.