Theoretical investigation of hydrogen- and halogen-terminated c-BN (111) clusters

The surface stabilizing properties of different species X (X = H, F, Cl, Br ) on B(111) and N(111) c-BN cluster surfaces, have been investigated theore tically within:the density-functional theory method. Calculated adsorption energies indicated that all species were found efficient in terminating the different cluster surfaces. However, Br species induce large sterical hind rances and thus disable the stabilization of especially a N(111) surface. F or comparison, the surface stabilization properties of H and F on crystalli ne surfaces were also investigated. These species were, With one exception, even more efficient as surface stabilizing agents. However, there was hard ly any effect for the adsorption of F on the crystalline N(111) compared to the corresponding smaller cluster surface. The adsorbed H and F species on the crystalline B(111) and N(111) surfaces, respectively, have been found, with one exception, to have a large possibility for surface migration and/ or gas-phase abstraction. The F species adsorbed to the B(111) surface will most probably block the growth sites on that very surface. [S0163-1829(99) 14547-8].