Mechanism for diamond growth on hydrogenated {111} surfaces of cubic boronnitride

Chemical reactions between hydrogen atoms or methyl radicals and hydrogenat ed {111} surfaces of cubic boron nitride clusters during diamond growth are investigated using the semiempirical molecular orbital method of AM1 appro ximation. The heat of formation (H.O.F.) estimated at the first stage of gr owth suggests product formation following the lowest energy path. Also, che mical interactions are discussed based on the calculated electronic energy levels of the fragments of clusters or methyl radicals. The results explain why diamond nuclei grow favorably on {111}B surfaces but not on {111}N one s, and the nucleation of diamond proceeds easily under the influence of alt ernating charge (+ and -), pulsed positive charge, or positive charge bias to the substrate.