Surface migration during diamond growth studied by molecular orbital calculations

Migration of various important species (H, CH3, CH2, C2H, and C2H2 on a dia mond (111) surface has been investigated theoretically, using a cluster app roach and the second-order Moller-Plesset perturbation theory. The order of the energies (barriers) obtained for a single jump between two neighboring radical sites is CH2<H<C2H approximate to CH3 (52, 248, 350, and 353 kJ/mo l, respectively). The C2H2, species is assumed to migrate by an alternating onefold and difold site adsorption to the surface. The corresponding barri er obtained for C2H2 is 186 kJ/mol, which is somewhere in between that of C H2 and H. The present type of surface migration of chemisorbed species will , with one exception, be energetically favorable in comparison to any desor ption process. In the case of C2H2, a desorption process will be energetica lly favorable. [S0163-1829(99)00812-7].