Nano-structured nitrogenated carbon films - morphology and field emission

Crystalline nitrogenated carbon (C:N) films have been successfully synthesi sed by plasma-enhanced hot filament chemical vapour deposition (PE-HF-CVD). Nitrogen gas (N-2) and ammonia (NH3) were used as sources of atomic nitrog en whereas methane (CH4) acted as a carbon precursor. Structure analysis re veals the growth of a new type of ON film characterised by various polymorp hs including worm- and foil-like microstructures at the nanometer scale. Th e effects of bias voltage and filament temperature on the film morphology a re investigated in detail. Using pure Si as a substrate results in growth o f homogeneous nanostructured films, whereas arrays of nanotubes were deposi ted on Ni-coated substrates. Field emission in vacuum was observed on C:N f ilms deposited on pure Si above applied fields of 15 V/mum. The onset field could be decreased below 4 V/mum with Ni-coated substrates due to the pres ence of well-separated nano-tubular structures. (C) 2001 Elsevier Science B .V. All rights reserved.