Dependence of the composition and bonding structure of carbon nitride films deposited by direct current plasma assisted pulsed laser ablation on the deposition temperature

Carbon nitride films were deposited by direct current plasma assisted pulsed laser ablation of a graphite target under nitrogen atmosphere. Atomic force microscopy (AFM), Fourier transform infrared (FTIR), Raman, and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology, bonding structure, and composition of the deposited films. The influence of deposition temperature in the range 25-400 degreesC on the composition and bonding structure of carbon nitride films was systematically studied. AFM images show that surface roughness and cluster size increase monotonically with deposition temperature. XPS, FTIR, and Raman spectra indicate directly the existence of C-N, C=N, and Cequivalent toN bonds in the deposited films. The increase of deposition temperature results in a drastic decrease in the N/C ratio, the content of Cequivalent toN bond and N atoms bonded to sp(3) C atoms, in addition to the increase in the content of disorder sp(2) C atoms and N atoms bonded to sp(2) C atoms in the deposited films. Raman spectra show that the intensity ratio of D peak over G peak increases with increasing deposition temperature to 200 degreesC, then decreases with the further increase of deposition temperature, which results from the continuous growth of sp(2) cluster in the films. (C) 2002 Elsevier Science B.V. All rights reserved.