Abstract
Carbon nitride films were grown on Al 2 O 3 –TiC substrates by reactive pulsed KrF excimer laser ablation of graphite targets. Nitrogen contents up to 19 at.% were obtained by increasing the nitrogen partial pressure, P N2 to 75 mtorr. The effects of P N2 on the chemical bond structure and nanomechanical properties of CN x films were investigated by Raman, Fourier transform infra-red, X-ray photoelectron spectroscopies and nanoindentation. Quantitative analysis of the Raman spectra indicated that the introduction of nitrogen induced a progressive long-range order in the amorphous carbon and an increase in the size of sp 2 graphitic clusters. On the whole, the spectroscopic results suggest an increase of N-sp 2 hybridised C sites with increasing P N2 . Additionally, Raman spectroscopy established the presence of CN bonds at high P N2 . Both the hardness and Young's modulus were significantly reduced from 45 and 463 GPa for pure carbon to 2 and 51 GPa at N concentration of 19 at.%. The deterioration of the nanomechanichal properties with N incorporation is attributed to a transition from an amorphous structure consisting of predominately sp 3 C bonds to a polymeric like structure involving predominately double bonded C and N atoms.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call