Banner
WideGap2001
 Shield
Index

Doping Issues in Wide Band-Gap Semiconductors

Exeter, United Kingdom
21-23 March 2001
Next

Poster abstract

Defects in beryllium doped GaN modelled by local density functional theory

C. D. Latham (1,2,3)

(1) Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT, Finland, (2) Department of Mathematics, Luleå University of Technology, SE-97187 Luleå, Sweden, (3) School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom

R. M. Nieminen (1), S. Öberg (2), C. J. Fall (3), R. Jones (3), P. R. Briddon (4)

(1) Laboratory of Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT, Finland, (2) Department of Mathematics, Luleå University of Technology, SE-97187 Luleå, Sweden, (3) School of Physics, University of Exeter, Exeter EX4 4QL, United Kingdom, (4) Department of Physics, University of Newcastle upon Tyne, Newcastle, NE1 7RU, United Kingdom

The problem of beryllium doping in gallium nitride has been investigated using the AIMPRO local-density-functional theory based method. Three defects are considered: substitional beryllium acceptors, interstitial beryllium atoms, and a beryllium pair near to a vacant gallium lattice site. The formation energy of a neutral Be acceptor is found to be approximately 2.4 eV, in good agreement with the value of 2.2 eV calculated earlier by Neugebauer and Van de Walle.[1] Interstitial Be lies very close to the hexagonal site on a nitrogen plane. The substitutional-interstitial pair is very strongly bound with an energy of approximately 4.2 eV. It is a deep donor; thus its formation provides a possible explaination the poor doping efficiency of Be in GaN.

[1] J. Neugebauer and C. G. Van de Walle, J. Appl. Phys., 85, 3003-3005 (1999)