American Physical Society, Physical review B, 19(75), 2007
DOI: 10.1103/physrevb.75.193201
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We use positron annihilation spectroscopy to study 2 MeV 4He+ -irradiated InN grown by molecular-beam epitaxy and GaN grown by metal-organic chemical-vapor deposition. In GaN, the Ga vacancies act as important compensating centers in the irradiated material, introduced at a rate of 3600 cm exp −1. The In vacancies are introduced at a significantly lower rate of 100cm−1, making them negligible in the compensation of the irradiation-induced additional n-type conductivity in InN. On the other hand, negative non-open volume defects are introduced at a rate higher than 2000cm exp −1. These defects are tentatively attributed to interstitial nitrogen and may ultimately limit the free-electron concentration at high irradiation fluences. ; Peer reviewed