STABILITY AND RECONSTRUCTION OF DIAMOND (100) AND (111) SURFACES

Results of scanning tunnelling microscopy (STM) and molecular dynamic (MD) annealing studies based on quantum mechanically derived interatomic forces using a semiempirical density functional approach are combined for analysing diamond surface structures. Experimentally obtained STM images of diamond (100) and (111) faces on polycrystalline films reveal (1 x 1), (square-root 3 x square-root 3) R30-degrees and possibly (2 x 1) structures. The (100) faces show stable (2 x 1) reconstruction with dimer formation. Surface structures with and without adsorbed hydrogen are determined and their stability is proved by MD simulated annealing techniques. The bulk-like (111) and (square-root 3 x square-root 3) R30-degrees structures, as they are observed on grown (111) facets, are attributed to the two different single-atomic (111) layers, which supports growth mechanisms in which the two alternating single-atomic layers grow by turns and not simultaneously.