Physical Review B, 60(22), 15117-15122 (1999)

Density-functional calculations of carbon diffusion in GaAs

C. D. Latham (a), M. Haugk (b), R. Jones (a), Th. Frauenheim (c), P. R. Briddon (d)

(a) School of Physics, University of Exeter, Exeter, EX4 4QL, United Kingdom

(b) Institut für Physik, Theoretische Physik III, Technische Universität, D-09107 Chemnitz, Germany

(c) Theoretische Physik, Fachbereich Physik, Universität-GH Paderborn, D-33098 Paderborn, Germany

(d) Department of Physics, University of Newcastle, Newcastle, NE1 7RU, United Kingdom

(Received 12th May 1999)

Abstract

Self-consistent-charge density-functional tight-binding (SCC-DFTB) calculations have been performed to survey the potential-energy surface for a single interstitial carbon atom introduced into GaAs.  The results provided a possible model for the diffusion of carbon through GaAs with an activation energy of less than 1 eV.  The carbon atom moves via split-interstitial and bond-centered configurations.  Subsequently, the energetics of the model reaction were refined using a fully self-consistent density-functional method, AIMPRO.  These calculations were found to be in good agreement with the more approximate SCC-DFTB results.  Experimental studies have also found an activation energy of ~1 eV for carbon migration in heavily doped material.

PACS: 66.30.Jt, 61.72.Bb, 61.72.Ji, 71.15.Nc

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