Amorphization of carbon materials studied by X-ray photoelectron spectroscopy

Takahiro, Katsumi*; Terai, Atsushi*; Oizumi, Shinnosuke*; Kawatsura, Kiyoshi*; Yamamoto, Shunya; Naramoto, Hiroshi

X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy have been applied to investigate amorphization processes by ion irradiation for various carbon materials, including highly oriented pyrolytic graphite (HOPG), isotropic graphite, glassy carbon (GC) and C crystalline film. It is found that the asymmetry of the XPS C 1s line increases as the irradiation dose increases. The origin of the asymmetry appeared on the C 1s line is discussed. It is concluded that the asymmetry of the C 1s line is not correlated with the increase in the size of a graphitic layer, but is related with the structural disorders, such as a bond angle disorder.