Vacuum Annealing Formation of Graphene on Diamond C(111) Surfaces Studied by Real-Time Photoelectron Spectroscopy

Abstract

To clarify the graphene formation process on a diamond C(111) surface, changes in the chemical bonding state caused by annealing in vacuum were investigated by photoelectron spectroscopy using synchrotron radiation. It was difficult to study the formation of sp2-bonded carbon atoms on a diamond C(111) surface using photoelectron spectroscopy because the peak of the sp2 component overlaps the peak of the surface sp3 component as a result of the 2×1 reconstruction. Therefore, we focused on the shift in the C 1s photoelectron spectra and energy loss spectra caused by band bending depending on the temperature. As a result, we found that graphitization on the diamond C(111) surface began at approximately 1120 K, which was lower than that for a SiC substrate. The obtained photoelectron spectra indicated that a buffer layer composed of sp2-bonded carbon atoms existed at the interface between graphene and the diamond C(111) surface.

Surface Modifications of Nanodiamonds and Current Issues for Their Biomedical Applications

“…Diamond graphitization can be induced by different mechanisms: via thermal treatment under vacuum [134,135] or exposure to reactive gas under ambient atmosphere [136][137][138]. It can be also obtained by beam irradiation (electron, ion, laser, gamma-ray) [139][140][141].…”

Theoretical investigation of the electronic structure and quantum transport in the graphene–C(111) diamond surface system

“…(c) Perspective view of the hybrid system, illustrating transport direction along the ridges (A) and normal to the ridges (B). and recent observations (Ogawa et al 2012) indicate that this surface reconstruction may initiate a step-by-step conversion of the topmost diamond layer to graphene under ultrahigh vacuum conditions at temperatures above 1300 K. The structure of the graphene-diamond hybrid system, which we consider here, is illustrated in figure 1.…”

Surface Modifications of Nanodiamonds and Current Issues for Their Biomedical Applications

“…As a consequence, some oxidized groups and non-diamond carbon may remain at the surface. The selectivity of these gaseous treatments is often limited: after heating in ammonia flow, aminogroups, C≡N and C=N-containing groups were identified at ND surface [132,133]. In order to create more reactive species, a CF4 atmospheric pressure plasma was used [95].…”