Preparation of amorphous carbon films by layer-by-layerhydrogen plasma annealing method and their luminescence properties

A layer-by-layer hydrogen plasma annealing method was used to fabricate hydrogenated amorphous carbon (a-C:H) films in plasma chemical vapor deposition system by using methane and hydrogen as the reactant gases. The influences of hydrogen annealing conditions on the structures and photoluminescence behavior were systematically investigated. It was found that the photoluminescence (PL) properties of a-C:H films were strongly affected by the hydrogen plasma annealing process. The PL characteristics are believed to relate to the film network relaxation rather than the change of the optical band gap. Two intense PL bands, which were located at both the green and blue-violet regions, were observed at room temperature. For some annealed a-C:H films, the resonant features were observed in photoluminescence excitation spectra, which is consistent with the exciton-like recombination model. (C) 2002 Elsevier Science B.V. All rights reserved.