PHOTOCONDUCTIVITY AND AFM STUDY OF NITROGEN-DOPED A-DLC FILMS

We present the results of photoconductivity, photosensitivity, and dec ay 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 sourc e of carbon. Several films were doped employing nitrogen (N-2) as dopi ng gas. The spectral response of photosensitivity of doped films shift s to higher energy, similar to the measured optical energy gap of thes e films. Unlike the photosensitivity, the photocurrent of doped film i s larger by two orders of magnitude than that of nondoped film. The mo bility 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 pr operties of the a:DLC and N-DLC films surface we have used the atomic force microscope. (C) 1998 Elsevier Science S.A.