Morphological change of carbon surfaces by sputter erosion

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°. The irradiation fluence was 2 × 1017 cm−2 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.