Photovoltaic properties of an amorphous carbon/fullerene junction

This paper demonstrates all-carbon photovoltaic devices made of amorphous carbon (a-C) and C60 thin films. C60 film is deposited by the sublimation in vacuum and a-C film is synthesized by exposing N2 radicals to C60 during the deposition. C60 is converted into a-C when the rf power is larger than 150 W and the optical band gap decreases with increasing the power. Photovoltaic properties of device with the structure of Al/C60/a-C/indium tin oxide/glass are presented. It is shown that the present cell has a strong spectral response in the wavelength range shorter than 550 nm and a small response at around 620 nm.