Surface Properties of Diamond (111): 1 × 1, 2 × 1, and 2 × 2 Reconstructions

Stable clean and hydrogenated (111) surface reconstructions found by density-functional molecular dynamics (DF-MD) are characterized in terms of their vibrational and electronic properties. Electronic charge density distributions at the surface and surface projected vibrational densities of states (VDOS) are compared with recent experiments (STM, HREELS). They represent signatures of the considered surfaces that might be used to understand and to classify as-grown surfaces. In particular, we prove hydrogenated (2 × 1) reconstructed chains to coexist next to a (2 × 2) reconstruction formed by adsorbed CH3 radicals on the same as-grown (111) facet. The implications of the simultaneous detection of both surface reconstructions for diamond growth are discussed.