Plasma characterization during laser ablation of graphite in nitrogen for the growth of fullerene-like CNx films

TLDR: In this paper, the chemistry, energy, and spatial distribution of species in carbon-nitrogen plasma plumes were investigated to define plasma conditions for growth of carbon nitride CNx films with a fullerene-like structure.

Abstract: Chemistry, energy, and spatial distributions of species in carbon–nitrogen plasma plumes were investigated to define plasma conditions for growth of carbon nitride CNx films with a fullerene-like structure. Plumes were generated by ablation of graphite using a 248 nm excimer laser in the presence of low-pressure nitrogen. The plumes were investigated using element specific imaging, time-of-flight experiments, fluorescence spectroscopy, and molecular vibration sequence analyses. Studies showed the importance of plume/substrate interaction in causing secondary excitation phenomena. For N2 pressures within the 5–50 mTorr range, plasmas at the substrate vicinity were found to consist mostly of atomic carbon, CN and C2 molecules. Kinetic energies were calculated within 10–20 eV for mono atomic carbon, 30–55 eV for CN, and 20–40 eV for C2. Excited CN and C2 molecules were generated by laser ablation and by collisions of the plume with the substrate surface. Their vibrational energies were strongly influenced by...