Synthesis of new carbon-nitrogen nanoclusters by annealing diamond-like carbon films in nitrogen
Annotatsiya
Diamond-like carbon (DLC) films were prepared by ion-beam sputtering of a graphite target and annealed at a temperature of 400°C in vacuum and nitrogen with oxygen admixture (about 1–2%). The Raman and optical absorption spectra of these films were studied. Anomalous changes in the DLC films annealed in nitrogen were detected. The optical absorptance of films in the visible range of the spectrum decreased by approximately two orders of magnitude; the D and G lines of graphene nanoclusters disappeared in the Raman spectra, while new narrow lines at 928, 968, and 2324 cm−1, as well as a broad line at 2200–2400 cm−1, arose. These changes were found to be reversible. Subsequent annealing of the films in vacuum (400°C) restored the optical properties and Raman spectra of the samples. The results obtained are indicative of the formation of new carbon-nitrogen nanoclusters under certain conditions of annealing of a DLC film.