Elimination of defects in In–Mg codoped GaN layers probed by strain analysis

The effect of In codoping effect in GaN:Mg layers were investigated through strain analysis. A hydrostatic lattice expansion is induced by In doping which cannot be simply explained by the size effect of In and Mg dopants. Together with the photoluminescence spectrums, this lattice expansion is a strong evidence for the elimination of nitrogen vacancies. The biaxial strain and edge dislocations are reduced with In doping. A theoretic model of interaction between In atoms and edge dislocations are established to explain this phenomenon.