On the nature of carbon nitride nanocrystals formed by plasma enhanced chemical vapor deposition and rapid thermal annealing

Using high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy, carbon nitride nanocrystals were observed in films deposited by RF plasma-enhanced chemical vapor deposition (RF-PECVD) followed by a rapid thermal annealing (RTA) to 1000°C. The (30±10) nm crystals are embedded in an amorphous matrix, and the interplanar lattice spacings suggest that the crystals are the hexagonal β-carbon nitride phase. Investigations using Fourier transform infra-red spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) of the films show that RTA increases the sp3 content of the films but decreases the CN (nitrile), N–H and C–H content.