Calculated properties of point defects in Be-doped GaN
2003 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 67, no 20, 205206- p.Article in journal (Refereed) Published
The properties of several point defects in hexagonal gallium nitride that can compensate beryllium shallow acceptors (BeGa) are calculated using the AIMPRO method based on local density functional theory. BeGa itself is predicted to have local vibrational modes (LVM's) very similar to magnesium acceptors. The highest frequency is about 663 cm-1. Consistent with other recent studies, we find that interstitial beryllium double donors and single-donor beryllium split interstitial pairs at gallium sites are very likely causes of compensation. The calculations predict that the split interstitial pairs possess three main LVM's at about 1041, 789, and 738 cm-1. Of these, the highest is very close to the experimental observation in Be-doped GaN. Although an oxygen donor at the nearest-neighboring site to a beryllium acceptor (BeGa-ON) is also a prime suspect among defects that are possibly responsible for compensation, its highest frequency is calculated to be about 699 cm-1 and hence is not related in any way to the observed center. Another mode for this defect is estimated to be about 523 cm-1 and is localized on the ON atom. These two vibrations of BeGa-ON are thus equivalent to those for the isolated substitutional centers perturbed by the presence of their impurity partners.
Place, publisher, year, edition, pages
2003. Vol. 67, no 20, 205206- p.
density functional theory, doping, point defects, positron annihilation, infrared spectroscopy, semiconductors, III-V, nitrides, GaN, Natural sciences - Physics, Materials science - Functional materials
Naturvetenskap - Fysik, Teknisk materialvetenskap - Funktionella material
Research subject Scientific Computing
IdentifiersURN: urn:nbn:se:ltu:diva-6938DOI: 10.1103/PhysRevB.67.205206Local ID: 544d0880-bffc-11db-834c-000ea68e967bOAI: oai:DiVA.org:ltu-6938DiVA: diva2:979824
Validerad; 2003; 20070219 (kani)2016-09-292016-09-29Bibliographically approved