Raman and infrared modes of hydrogenated amorphous carbon nitride

Features in the Raman and infrared (IR) spectra of highly sp(3) bonded hydr ogenated amorphous carbon nitride films are assigned. The Raman spectra sho w three main features all found in a-C itself, the G and D peaks at 1550 an d 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 cluste rs. The intensity of the L mode is found to scale with the D mode, supporti ng its identification as an in-plane rotational mode of sixfold rings in gr aphitic 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 ef fect on the IR spectra at 1100-1600 cm(-1) making this band asymmetric towa rds the 1600 cm(-1) region. (C) 2001 American Institute of Physics.