Carbon Nitride Thin Films Grown by Pulsed Laser Deposition

Abstract

AbstractThin films of diamond and diamond-like carbon (DLC) are technologically important materials that serve as hard, scratch resistant and chemically inert coatings for tools and optics. Recent calculations suggest that β-C3N4 should be harder than diamond. We have deposited carbon nitride (CNx) thin films by pulsed laser deposition. The films were grown from a graphite target in a nitrogen background. The nitrogen source was either (a) a N2 gas atmosphere, or (b) a N2+/N+ ion beam generated by a Kaufman ion gun. A wide range of deposition parameters were investigated, such as deposition pressure (0.3-900 mTorr N2), substrate temperature (50 and 600°C), and laser fluence (1-4 J/cm2) and laser repetition rate (1-10 Hz). The films have been characterized by Rutherford Backscattering Spectroscopy, thin-film X-ray diffraction, scanning electron microscopy, and micro-Raman spectroscopy. In general, the films were nitrogen deficient with a maximum nitrogen to carbon ratio (N/C) of 0.45 and a shift in the G band Raman peak consistent with amorphous CNx (a-CNx).