Highly photoconductive amorphous carbon nitride films prepared by cyclic nitrogen radical sputtering

We report on the growth of amorphous carbon nitride films (a-CNx) showing the highest conductivity to date. The films were prepared using a layer-by-layer method (a-CNx:LL), by the cyclical nitrogen radical sputtering of a graphite radical, alternated with a brief hydrogen etch. The photosensitivity S of these films is 10(5), defined as the ratio of the photoconductivity sigma(p) to the dark conductivity sigma(d) and is the highest value reported thus far. We believe that the carriers generated by the monochromatic light (photon energy 6.2 eV) in the a-CNx:LL films are primarily electrons, with the photoconductivity shown to increase with substrate deposition temperature. (C) 2004 American Institute of Physics.