title: Theoretical Investigations of the Reactions of N- and O-Containing Species on a C(100):H 2 × 1 Reconstructed Diamond Surface.
abstract: Quantum mechanical and hybrid quantum mechanical/molecular mechanical cluster models were used to investigate possible reaction mechanisms whereby gas-phase NHx(x = 0-2), CNHx(x = 0, 1), and OH radicals can add to, and incorporate in, a C-C dimer bond on the C(100):H 2 × 1 diamond surface during chemical vapor deposition (CVD) from microwave-activated C/H containing gas mixtures containing trace amounts of added N or O. Three N incorporation routes are identified, initiated by N, NH, and CN(H) addition to a surface radical site, whereas only OH addition was considered as the precursor to O incorporation. Each is shown to proceed via a ring-opening/ring-closing reaction mechanism analogous to that identified previously for the case of CH3addition (and CH2incorporation) in diamond growth from a pure C/H plasma. On the basis of the relative abundances of N atoms and NH radicals close to the growing diamond surface, the former is identified as the more probable carrier of the N atoms appearing in CVD grown diamond, but fast H-shifting reactions postaddition encourage the view that NH is the more probable migrating and incorporating species. CN radical addition is deemed less probable but remains an intriguing prospect, since, if the ring-closed structure is reached, this mechanism has the effect of adding two heavy atoms, with the N atom sitting above the current growth layer and thus offering a potential nucleation site for next-layer growth.
authors.affiliation: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Kelly
authors.affiliation: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Halliwell
authors.affiliation: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors.forename: W Jeff
authors.initials: WJ
authors.lastname: Rodgers
authors.affiliation: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Pattle
authors.affiliation: K.U. Leuven , Department of Chemistry, Celestijnenlaan 200F, B-3001 Heverlee, Belgium.
authors.forename: Jeremy N
authors.identifier: http://orcid.org/0000-0002-1728-1596
authors.initials: JN
authors.lastname: Harvey
authors.affiliation: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors.forename: Michael N R
authors.identifier: http://orcid.org/0000-0001-5762-7048
authors.initials: MN
authors.lastname: Ashfold