Ab initio study of metastability of Eu3+ defect complexes in GaN

Abstract

Density functional theory (DFT) within the generalized gradient approximation (GGA) has been used to study the structural and electronic properties of Eu3+ defect complexes in GaN under Ga-rich conditions. Two distinct configurations of the EuGaVN defect complex, the axial and basal configuration, have been investigated. We report two forms of metastable defects namely; the Negative U defect in the lower half of the GaN band-gap and a metastable defect with two distinct configurations each with levels at EC −0.46eV and −0.56eV in the upper half of the GaN band-gap.