RAMAN SCATTERING STUDIES ON THE STRUCTURAL PROPERTIES OF PULSED LASER DEPOSITED AMORPHOUS CARBON NITRIDE THIN FILMS

Abstract

Raman scattering analysis revealed that the structure of carbon films prepared by pulsed laser deposition (PLD) at room temperature is predominantly amorphous and the structure of amorphous carbon nitride ( a-CN x) thin films can be changed with varying substrate temperatures (ST) from 20°C to 500°C. The deposited a-CN x films are composed of C – N , C ≡ N and C – O bonded materials and the C – N and C ≡ N bonds are increased with ST. We have found that no other obvious peaks can be distinguished in the range 900–2300 cm-1 in which several peaks always appear in a-CN x films. The spectra were deconvoluted into Raman D and G peaks and the structural parameters are determined. The upward shifts of the Raman G peak towards 1592 cm-1 shows the evidence of a progressive formation of crystallites in a-CN x films upon increase of ST. While the upward shifts of the Raman D peak towards 1397 cm-1 have been related to the decrease of bond-angle disorder and sp3 tetrahedral bonding in its structure. Raman FWHM and I D /I G also indicate that N incorporation with increase of ST caused an increase in the number and/or size of graphitic domains in the a-CN x films.