Influence of point defects on optoelectronic properties of Al0.375Ga0.625N

Results show that the Al0.375Ga0.5625N crystal with Ga vacancy and the Al0.3125Ga0.625N crystal with Al vacancy show p-type property, meanwhile, the Al0.375Ga0.625N0.9375 crystal with N vacancy show n-type property. The Fermi level of Al0.375Ga0.5625N and Al0.3125Ga0.625N enter into valence band while the Fermi level of Al0.375Ga0.625N0.9375 enters into conduction band. The formation energy of N vacancy is the lowest, showing it is the easiest for N vacancy to exist. The global transfer index values of the defective crystals are all lower than that of the pure one. The bond populations around the defects increase because of the shorter bonds. For the defective crystals, there appear new abnormal dispersion ranges at the low energy region, and the reflectivities of the defective crystals are higher than that of the pure one at the range of 0-2 eV.