C-13 NMR AND FTIR STUDY OF THERMAL ANNEALING OF AMORPHOUS HYDROGENATED CARBON

Amorphous hydrogenated carbon deposited from acetylene in a dc glow di scharge has been studied using solid-state C-13 NMR and FTIR spectrosc opies. The fraction of sp2 carbon and the fraction of sp2 carbons that bear a proton increase from 0.39 and 0.33, respectively, for the as-d eposited material to approximately 1.0 and 0.44, respectively, after a nnealing at 500-degrees-C. The loss of aliphatic carbon with increasin g temperature arises not from aromatization but from outgassing of hyd rocarbons or evolution of CO and CO2 formed by reactions between oxyge n and the film. Infrared spectra are presented which show absorption f eatures not previously seen for this material. The changing structure with heat treatment and the role of oxygen in the formation and modifi cation of the material are discussed.