Magnetic and structural properties of Fe-implanted GaN at room temperature

Abstract

GaN grown by metal-organic chemical vapour deposition on the sapphire substrate was implanted with 3 MeV Fe10+ ions to fluences of 1 × 1013 to 5 × 1015 ions/cm2 at room temperature. The change of magnetic property with the implantation fluence was measured by vibrating sample magnetometer. The structural features, including implantation-induced interstitials and vacancies, were studied by a combination of Raman spectroscopy, photoluminescence spectroscopy, transmission electron microscopy and positron annihilation technology. The ferromagnetic behaviour was observed in the as-grown sample, and the saturation magnetization reached the maximum after the Fe implantation to a fluence of 5× 1013 ions/cm2. With increasing fluence, it decreased to be even smaller than that of the as-grown sample. The possible reasons are discussed.