Electronic and optical properties of carbon nitride thin films synthesized by laser ablation under ion beam bombardment

Abstract

Carbon nitride thin films were deposited by 532 nm Nd:YAG laser ablation of graphite assisted by a nitrogen ion beam bombardment on silicon substrates. Different nitrogen ion beam energies (200, 400, and 600 eV) were used while the laser parameters remained fixed. X-ray photoelectron spectroscopy (XPS) and ellipsometry measurements were carried out to analyze the electronic and optical properties. The XPS C 1s spectrum for the C–N binding is at 286.5 eV while the N 1s spectrum has a corresponding peak of C–N binding at 396.9 eV. The optical gap Eopt is on the order of magnitude of 10−1 eV and increases with the N/C ratio in the deposited film. Linear dependence of the refractive index n and the extinction coefficient k on photon energy E in the range of 1.5–3.5 eV are established.