Jc. Sanchez-lopez et al., Bonding structure in amorphous carbon nitride: A spectroscopic and nuclearmagnetic resonance study, J APPL PHYS, 90(2), 2001, pp. 675-681
Since the prediction of Liu and Cohen [Science 245, 841 (1989)] of the pote
ntial extraordinary mechanical properties of crystalline beta -C3N4, many a
uthors have attempted its synthesis. However, in most cases, the obtained m
aterials are amorphous phases with a complex bonding structure. Their chara
cterization is complicated due to the absence of a reference compound, the
lack of long-range order, and the poor knowledge about their bonding struct
ure. In this article, we present H-1, C-13, and N-15 solid-state nuclear ma
gnetic resonance (NMR) measurements for the determination of the bonding ty
pes in amorphous CNx films. NMR measurements do not require long-range orde
r and are able to clearly identify the signals from the sp(2)- and sp(3)-bo
nded phases. The analysis of the data obtained by other characterization te
chniques, such as infrared spectroscopy, x-ray photoelectron spectroscopy,
electron energy-loss spectroscopy, and x-ray absorption near-edge spectrosc
opy on the same sample, based on the information acquired by NMR, enables t
he description of a structure model for the studied amorphous-CNx phase pre
pared by dc-magnetron sputtering and to revise the interpretation found in
the literature. (C) 2001 American Institute of Physics.