An investigation was made of gallium and nitrogen vacancies in bulk gallium nitride and nanowires using self-interaction corrected pseudopotentials. In particular, the band structures were examined in order to compare and contrast differences between the self-interaction corrected pseudopotential results and standard density functional theory results using a generalized gradient approximation (Perdew et al, 1996) functional. For pure nanowires, similar trends were observed in the band-gap behaviour, with the gap decreasing for increasing nanowire diameters (with larger band-gaps using self-interaction corrected pseudopotential). For gallium vacancies in bulk GaN and GaN nanowires, self-interaction corrected pseudopotential results were similar to density functional theory - generalized gradient approximation results, albeit with larger band-gaps. Nitrogen vacancies in bulk GaN showed similar defect-induced states near the conduction band, whilst a lower lying defect state was observed below the valence band for the density functional theory - generalized gradient approximation calculations and above the valence band for the self-interaction corrected pseudopotential results. For nitrogen vacancies in GaN nanowires, similar defect states were observed near the conduction band, however, while the self-interaction corrected pseudopotential calculations also showed a defect state/s above the valence band, it was not possible to locate this state for the density functional theory - generalized gradient approximation calculations (possibly because it was hybridized with edge states and buried below the valence band).

Vacancies in GaN Bulk and Nanowires: Effect of Self-Interaction Corrections. D.J.Carter, M.Fuchs, C.Stampfl: Journal of Physics - Condensed Matter, 2012, 24[25], 255801