CHARACTERIZATION AND MODIFICATION OF CARBON NITRIDE FILMS DEPOSITED BY LASER-ABLATION UNDER LOW-ENERGY ION-BEAM BOMBARDMENT

Carbon nitride thin films with N-concentration about 41% were synthesi zed by YAG pulsed laser ablation of graphite under a low-energy (< 50 eV) nitrogen ion-beam bombardment. The results of electron diffraction (ED) and X-ray photoelectron spectroscopy (XPS) analyses suggested th e existence of beta-C3N4 polycrystallite grains in the amorphous carbi de matrix of the deposited films. Optical emission spectra of the lase r produced graphite plasma using different output wavelengths of a Nd: YAG laser, 355, 532 and 1064 nm were studied. The emission spectra sho wed that the plasma produced by the 355 and 1064 nm laser ablation con tained a high concentration of excited C-2 radicals while in the case of 532 nm ablation, a relatively higher concentration of excited atomi c carbon radicals was found in the plasma. A post-treatment of the dep osited films using low-energy (50 eV) nitrogen ion-beam bombardment wa s carried out in order to improve the concentration of beta-C3N4 struc tures in the films.