Photoconductivity and AFM study of nitrogen doped a:DLC films

We present the results of photoconductivity, photosensitivity, and decay time of photocurrent measurement as a function of temperature, for both nitrogen doped (N-DLC) and nondoped a:DLC films. The a:DLC films were deposited using RF glow discharge of methane gas (CH4) as a source of carbon. Several films were doped employing nitrogen (N-2) as doping gas. The spectral response of photosensitivity of doped films shifts to higher energy, similar to the measured optical energy gap of these films. Unlike the photosensitivity, the photocurrent of doped film is larger by two orders of magnitude than that of nondoped film. The mobility of doped films (2.43 x 10(-5)) is also larger by two orders of magnitude than the nondoped films (5.64 x 10(-7)) at room temperature. In order to provide nano-scale information about the morphological properties of the a:DLC and N-DLC films surface we have used the atomic force microscope. (C) 1998 Elsevier Science S.A.