Structure and Dynamics of Diamond (100) Surfaces at High Hydrogen Coverage

Publisher Website
Google Scholar
Abstract
The structural properties of hydrogenated diamond (100) surfaces have been investigated via a Tight-Binding model. For H coverages intermediate between the monohydrogenated and dihydrogenated surfaces, stable geometries consisting of monohydrogenated dimer units and dihydride units are found. When the H coverage is sufficiently high, the substrate lattice is found to distort in order to reduce steric repulsions between the dihydride units. We thereby obtain a novel structure for the dihydrogenated surface which is significantly more stable than those proposed previously. Tight-Binding Molecular Dynamics is used to illustrate a mechanism for the rapid removal of isolated monohydride units, which are, therefore, suggested to be kinetically as well as thermodynamically unstable.