Raman analysis of laser annealed nitrogen doped amorphous carbon film

A micro-Raman spectrometer has been used to study nitrogen doped amorphous hydrogenated carbon (a-C/H(N)) films, which are annealed by a focused argon ion (514.5 nm) laser operating at the power density of 300, 750 and 1500 W/mm2, respectively. The analysis shows that nitrogen atoms in the films mainly take the form of C–N bonds, which limits the forming of C–H bonds because the formation energy of C–N bond is higher than that of C–H bond. So the C–H bond in a-C/H film is easily decomposed, which increases the graphitization of film by laser annealing. On the other hand, C–N bonds are hardly decomposed in the course of laser annealing, then we consider that thermal stability of a-C/H(N) film increases with the increment of nitrogen content.