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 interatom ic forces using a semiempirical density functional approach are combin ed for analysing diamond surface structures. Experimentally obtained S TM images of diamond (100) and (111) faces on polycrystalline films re veal (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) reconstructio n with dimer formation. Surface structures with and without adsorbed h ydrogen are determined and their stability is proved by MD simulated a nnealing techniques. The bulk-like (111) and (square-root 3 x square-r oot 3) R30-degrees structures, as they are observed on grown (111) fac ets, are attributed to the two different single-atomic (111) layers, w hich supports growth mechanisms in which the two alternating single-at omic layers grow by turns and not simultaneously.