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The initial stages of deposition of graphene-like thin films have been studied by X-ray photoelectron spectroscopy, scanning electron microscopy, Raman spectroscopy and ellipsometry. The deposition process has been performed by sublimation of amorphous carbon on 330 nm SiO2/(001) Si substrates with surface area of 15× 15 mm². The sublimation process was carried out in a quartz tube having an internal diameter of 25 mm at a temperature of 1050°C in which samples were placed in an argon flow of about 1 cm³/s for 3 to 15 minutes. As a source of amorphous carbon, modified carbon blacks SPHERON 5000 were used. We established that an amorphous carbon film with thickness up to 3-6 nm is always deposited on the SiO2 after 3-5 min deposition and the deposition of a few-layered defected graphene as well as nano-sized graphite occurs after 5-6 min on the surface of substrate. Further on, after 8-10min deposition a non-continuous carbon film is formed and after 12-13 min the substrate is covered by a smooth and continuous carbon film. The film has extremely low resistivity (ρ= 2.8 × 10−6Ω.m) and consists of predominantly sp² hybridized carbon with a Raman spectrum similar to those of nano-sized graphene. [ABSTRACT FROM AUTHOR]

The modification of Cabot Corporation SPHERON 5000 carbon black by thermal treatment has been studied by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy. The thermal annealing was performed at temperatures ranging from 500°C to 1150°C for 3 hours in an air-atmosphere. XPS established that the satellite peak of hydrocarbons nearly disappears after treatment at temperatures over 1080°C. XRD reveals that the (002) reflection, due to graphitic ordered sp² hybridized carbon, shifts to its usual position at 2θ= 26.2° and that its full-width at half-maximum decreases with treatment at elevated temperatures. The reflection from (002) planes was sharpened while the relative intensity difference between it and those of (-111) and (011) planes increased, indicating stabilization in the predominately 2D carbon particles. The annealing at 1150°C causes enhancement of the formation of 3D graphitic nanocrystals as the intensity of (-110), (010), (-111), (011), (-112) and (012) planes increases nearly two times. The Raman studies confirmed the above conclusions. [ABSTRACT FROM AUTHOR]