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Energy and electronic structure of gallium and nitrogen interstitials in GaN Tilt Boundaries

Bere Antoine 1,2Belabbas Imad 1Gerard Nouet 1Pierre Ruterana 1Jean Koulidiati 2Chen Jun 3

1. SIFCOM, UMR6176, CNRS-ENSICAEN, 6 Bld Maréchal Juin, Caen 14050, France
2. Laboratoire de Physique et de Chimie de l'Environnement, Universite de Ouagadougou, Ouagadougou, Burkina Faso
3. Laboratoire Universitaire de Recherche d’Alençon, IUT d’Alençon (L), Damigny 61250, France


Defects containing point defects, impurities, and intentionally doping in GaN, are the subject of numerous experimental and theoretical investigations. It is well known that their presence can reduce the performance of optoelectronic devices due to a multiplicity of parasitic luminescence which they are responsible.
While it is now well known that yellow luminescence (YL) around 2.2 – 2.3 eV observed in undoped GaN layers results from a transition between band states and deep levels, the origin of the defects that are associated with this YL is still under debate.
Cathodoluminescence studies have recently shown that the YL is not uniform in the crystal and therefore can be associated with the presence of extended defects like dislocations and grain boundaries. Then, several atomistic models of extended defects may be considered in order to explore the ones that give rise to the parasitic YL.
In this work, molecular static atomistic simulations using a Self-Consistent-Charge Dentity-Functional-Tight-Binding (SCC-DFTB) approach will be applied to study the core structure of tilt boundaries in interaction with gallium and nitrogen interstitials. The geometry of the nearest neighbours, the formation energies and the electronic states associated to these defects will be discussed in comparison with those in GaN bulk and dislocations.


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Presentation: poster at E-MRS Fall Meeting 2005, Symposium F, by Bere Antoine
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-20 09:23
Revised:   2009-06-07 00:44