Raman and infrared modes of hydrogenated amorphous carbon nitride

Features in the Raman and infrared (IR) spectra of highly sp(3) bonded hydrogenated amorphous carbon nitride films are assigned. The Raman spectra show three main features all found in a-C itself, the G and D peaks at 1550 and 1350 cm(-1), respectively, and the L peak near 700 cm(-1). The intensity ratio of the D and G peaks, I(D)/I(G), is found to scale as (band gap)(-2), which confirms that nitrogen induces carbon to form sp(2) graphitic clusters. The intensity of the L mode is found to scale with the D mode, supporting its identification as an in-plane rotational mode of sixfold rings in graphitic clusters. A small feature at 2200 cm(-1) due to C=N modes is seen, but otherwise the Raman spectra resembles that of a-C and shows no specific features due to N atoms. The hydrogen content is found to have a strong effect on the IR spectra at 1100-1600 cm(-1) making this band asymmetric towards the 1600 cm(-1) region. (C) 2001 American Institute of Physics.