EFFECTS OF OXYGEN ON SURFACE RECONSTRUCTION OF CARBON

Recent experiments on diamond growth by chemical vapor deposition indi cate that atomic oxygen converts the diamond (100)-(2 x 1) surface to the (1 x 1) structure. Ab initio total energy calculations are perform ed on a cluster of carbon atoms simulating the (100) surface in order to investigate the effect of oxygen on surface reconstruction. Calcula tions are reported for the clean surface and for O atoms adsorbed atop carbon and at a C-C bridge site. Bridge and atop carbon sites for oxy gen have nearly identical adsorption energies and adsorption of O at e ither site prevents the C(100)-1 x 1 to 2 X 1 dimerization reconstruct ion. Adsorption of oxygen at one bridge site affects, but does not pre vent, the dimerization of an adjacent pair of surface carbon atoms.