Monitoring the structural and chemical properties of CNx thin films during in situ annealing in a TEM
Carbon nitride films synthesized by magnetron sputtering at different substrate temperatures have been studied using electron energy loss spectroscopy (EELS) during annealing performed in situ in a transmission electron microscope (TEM). The proportion of sp2 hybridized carbon slightly decreases initially during heating, presumably because of the removal of defects in the structure, whilst it increases at higher temperatures when graphitization tends to take place, as confirmed by high resolution electron microscopy (HREM). Substantial amounts of nitrogen (up to approximately 80%) are removed following annealing at 1000 °C. A corresponding decrease in the pre-peak of the nitrogen spectra suggests that pyridine-like N is released by annealing. As this peak component decreases, a second peak, of weaker intensity, is becoming apparent in the EELS spectra when the films are heated at temperatures above approximately 700 °C. The possibility has been suggested that this corresponds to N substituted for C in a graphitic structure, with possibly also some N2 contributing to the peak.
Grillo, S. E.; Hellgren, N.; Serin, V.; Broitman, E.; Colliex, C.; Hultman, L.; and Kihn, Y., "Monitoring the structural and chemical properties of CNx thin films during in situ annealing in a TEM" (2001). Educator Scholarship & Departmental Newsletters. 119.