Ripple formation on carbon surfaces by ion irradiation

Takahiro, Katsumi*; Kawatsura, Kiyoshi*; Zhang, K.*; Rotter, F.*; Schwen, D.*; Ronning, C.*; Hofsss, H.*; Krauser, J.*; Nagata, Shinji*; Yamamoto, Shunya; Narumi, Kazumasa

In order to study the allotropic effect on ripple formation on carbon surfaces induced by sputter erosion, three types of carbon materials, highly oriented pyrolytic graphite (HOPG), single crystalline diamond and tetrahedral amorphous carbon (ta-C) films, were irradiated with 5 keV Xe at an incident angle of 30 degree. The irradiation fluence was 210 cm for all irradiations. No ripples were formed on diamond and ta-C surfaces, while ripples with a wavelength of 100 nm occurred on HOPG. Electron energy loss spectroscopy revealed that the surfaces of all carbon materials became amorphous with similar densities upon irradiation. Therefore, the presented results clearly show that rippling depends on the nature of the underlying carbon materials. The mechanism for rippling of carbon materials will be discussed.