Study of carbon plasma for non-vacuum laser deposition

摘要

A new laser plasma technique for non-vacuum deposition of thin films has been developed recently. This technique was successfully applied to deposit hard carbon coatings on steel substrates. The obtained diamond-like carbon (DLC) coatings with amorphous structure demonstrated high nanohardness and good adhesion to the substrate. Here we present new experimental data concerning parameters of the produced carbon plasma and features of the plasma-substrate interaction, which are necessary for further progress of this technique. Spectroscopic study of the plasma emission was performed for picosecond and nanosecond laser pulses at different wavelengths (λ = 1078 nm, 539 nm and 248 nm). The laser plasma composition was studied and conditions for the occurrence of low-threshold air breakdown near the target surface were determined. The ranges of the substrate-target distances, which ensure carbon film deposition or plasma etching of the substrate, were determined. The revealed influence of the laser pulse energy, pulse duration and wavelength on the plasma-substrate interaction is reported.