Editors: | F. Kongoli, A. G. Mamalis, K. Hokamoto |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2018 |
Pages: | 352 pages |
ISBN: | 978-1-987820-88-1 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
The results of structural and optical investigations of thin carbon films deposited from the mass-separated beam of accelerated C60 ions with energy of 5 keV are presented. The substrate temperature ranged from 100°C to 400°C. It was established that change of the TS from 100°C to 400°C leads to the consecutive formation of diamond-like carbon (DLC) films with amorphous state and superhard nanocomposites consisting nanographite structures (1-2 nm) surrounded by a diamond-like amorphous matrix. For amorphous films the band gap (Eg) was in the range of 1.2 - 1.4 eV. For nanocomposite films on optical absorption spectra, there are two energy components: one with a narrow Eg = 1 eV, which is associated with three-dimensional nanocrystals of graphite, and the other - with a wide optical gap (Eg =3,45-3,55 eV) that corresponds to the diamond-like amorphous matrix of nanocomposite. According to the results of scanning tunneling microscopy (STM) and tunnel spectroscopy (TS), the size of graphite nanocrystals is about 1-2 nm and an amorphous shell around the graphite nanocrystals had a thickness of about 1.5 nm. The graphite component had n-type conductivity and an amorphous component had p-type conductivity. The electrical conductivity of such semiconductor nanocomposite was 103 S/m that to 6 orders higher compared to the DLC film in the amorphous state.