Time-Resolved Observation of Deposition Process of Ultrananocrystalline DiamondHydrogenated Amorphous Carbon Composite Films in Pulsed Laser Deposition

Abstract EN

Optical emission spectroscopy was used to study pulsed laser ablation of graphite in a hydrogen atmosphere wherein ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite films were grown on heated substrates.

Time-resolved photographs of a plume that expanded from a laser-irradiation spot toward a substrate were taken using a high-speed ICCD camera equipped with narrow-bandpass filters.

While the emissions from C atoms and C2 dimers lasted above the laser-irradiation spot on the target, the emission from C+ ions lasted above the substrate surface for approximately 7 microseconds, although the emission lifetime of species is generally approximately 10 nanoseconds.

This implies that C+ ions actively collided with each other above the substrate surface for such a long time.

We believe that the keys to UNCD growth in PLD are the supply of highly energetic carbon species at a high density to the substrate and existence of atomic hydrogen during the growth.