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Graphitization effects on diamond surfaces and the diamond/graphite interface

Jungnickel, G, Porezag, D, Frauenheim, T, Heggie, MI, Lambrecht, WRL, Segall, B and Angus, JC (1996) Graphitization effects on diamond surfaces and the diamond/graphite interface Physica Status Solidi (A) Applied Research, 154 (1). pp. 109-125.

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Abstract

Graphitic layers have previously been conjectured to play an active role in diamond nucleation by Lambrecht et al. and may also be involved in a mechanism for homoepitaxial diamond growth since the surfaces of diamond may partially graphitize under high-temperature conditions typical of growth processes. Recent molecular dynamics simulations of the diamond {111} surface, briefly reviewed and discussed here, indicate a progressive graphitization with increasing temperature which is strongly facilitated by any kind of surface perturbation or roughness such as step-like adsorbates. Here we show specifically that also twin boundaries promote graphitization. The process of debonding of the surface layer which is a simple displacive motion of the outer layer is also shown to be closely related to the delamination of the tetrahedrally bonded icosahedral C100 molecule into two concentric C20 and (fullerene-like) C80 fragments. In contrast, the tetrahedrally bonded icosahedral C300 molecule which contains one more concentric shell, does not spontaneously graphitize into a bucky onion (consisting of concentric C80 and C240 fullerenes) although the latter has lower energy. Progressive graphitization at a surface towards deeper layers before the top layer is delaminated can occur under certain conditions and then may lead to graphite/diamond prism plane interfaces similar to those previously investigated in connection with nucleation. The structural stability of the prism plane interface between graphite and diamond is re-investigated here. While the initial calculations with a classical potential underestimated the interface energy, the structural stability of the models previously presented is confirmed by the present quantum mechanical simulations.

Item Type: Article
Authors :
NameEmailORCID
Jungnickel, GUNSPECIFIEDUNSPECIFIED
Porezag, DUNSPECIFIEDUNSPECIFIED
Frauenheim, TUNSPECIFIEDUNSPECIFIED
Heggie, MIm.heggie@surrey.ac.ukUNSPECIFIED
Lambrecht, WRLUNSPECIFIEDUNSPECIFIED
Segall, BUNSPECIFIEDUNSPECIFIED
Angus, JCUNSPECIFIEDUNSPECIFIED
Date : 1 March 1996
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 12:43
Last Modified : 17 May 2017 12:43
URI: http://epubs.surrey.ac.uk/id/eprint/836467

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