Composition and chemical bonding of pulsed laser deposited carbon nitride thin films

Abstract

We studied composition, structure, and growth parameters of amorphous diamond-like carbon (DLC) and carbon nitride $({\mathrm{CN}}_x)$ films deposited by pulsed laser deposition in vacuum and in nitrogen atmosphere. The composition $\text{(0⩽}\mathrm{N/C}\text{⩽0.4),}$ the structural and the electronic properties of the deposited carbon and carbon nitride films were investigated for different laser fluences (1–12 J/cm²). Electron energy loss spectroscopy, x-ray photoelectron spectroscopy, and micro-Raman spectroscopy indicated an increase in ${\mathrm{sp}}^3$ -bonded carbon sites in the DLC films and an increase in $\mathrm{N}{\mathrm{-sp}}^3$ C bonded sites in the ${\mathrm{CN}}_x$ films with increasing deposition laser fluence. Raman spectroscopy also showed the presence of a small amount of C≡N bonds in the ${\mathrm{CN}}_x$ films. Furthermore, we observed that keeping the nitrogen pressure constant $\text{(P=100}$ mTorr) the increase in the deposition laser fluence is reflected by an increase in the nitrogen content in the films. All the results have been discussed in the framework of different theoretical models.