Preparation of the hard CN_X thin films using NO ambient gas by pulsed laser deposition

Pulsed laser deposition (PLD) technique has been widely used in thin film preparation because of its wonderful and excellent properties and amorphous carbon nitride (CN_X) thin films are recognized to have potential for applications like hard coating and electron field emission device. We have deposited CN_X thin films by KrF excimer laser (λ = 248 nm) ablation of pure graphite target in pure NO gas ambient condition. In this paper, we have prepared the CN_X thin films at various ambient NO gas pressure of 1.3-26 Pa and laser fluence of 2-5 J cm^-2 on Si (100) substrate. We consider that the hardness of CN_X thin films improves due to the increase the nitrogen/carbon (N/C) ratio. The N/C ratio depended on the ambient NO gas pressure and laser fluence. We obtained the maximum N/C ratio of 1.0 at NO 3.3 Pa. The typical absorption of CN bonds such as sp₂ C-N, sp³ C-N, G band and D band were detected from the infrared absorption measurement by FTIR in the deposited CN_X thin films.