The optical absorption band associated with the N vacancy in proton-irradiated samples of AlxGa1–xN, where x was 0.61 or 1, was investigated as a function of isothermal furnace annealing at 150 to 350C. The results showed that the enthalpy which was associated with the thermal migration process was 0.410 and 0.445eV, for Al0.61Ga0.39N and AlN, respectively. The variation in the full-width at half-maximum of the N vacancy absorption band in AlN, as a function of temperature, indicated that the electronic transition which was associated with the defect was coupled to a phonon with an energy of 0.0478eV. This phonon energy was in good agreement with the E2 phonon mode reported for AlN. A Frank-Condon shift of 1.142eV was also estimated from the full-width at half-maximum, measured as a function of temperature, and was indicative of a large lattice distortion in the vicinity of the defect.

Thermal Annealing Effect on Nitrogen Vacancy in Proton-Irradiated AlxGa1–xN. Q.Zhou, M.O.Manasreh: Applied Physics Letters, 2002, 80[12], 2072-4