Diamond and Related Materials, 3(11-12), 1370-1374 (1994)

The energetics of hydrogenic reactions at diamond surfaces calculated by a local spin-density functional theoretical method

C. D. Latham. (a), M. I. Heggie. (a), R. Jones. (b), P. R. Briddon (c)

(a) Department of Computer Science, University of Exeter, Exeter, EX4 4PT, UK

(b) Department of Physics, University of Exeter, Exeter, EX4 4QL, UK

(c) Department of Physics, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK

(Received 3rd December 1993; accepted in final form 9th March 1994)

Abstract

The energetics of reactions thought to be important in the growth of CVD diamond have been studied in detail by performing calculations based on the local spin-density functional theory.  These reactions are: (i) the abstraction of a hydrogen atom from a (111) diamond surface creating a surface dangling bond and (ii) the formation of reconstruction bonds on a diamond (100) surface by the removal of hydrogen molecules.  The results of two benchmark calculations are also given, namely hydrogen abstraction from methane and hydrogen exchange with methane.  The energetics of these reactions are found to be within 0.2 eV of the experimental values for barrier height and overall energy.  Data for diamond are less well known, but where comparisons are possible the accuracy of calculations seems to be similar.  For hydrogen abstraction by atomic hydrogen from a (111) surface the estimated barrier is slightly less than 0.4 eV and overall is energetically neutral.

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