Structural and magnetic properties of Co+ implanted n-GaN dilute magnetic semiconductors

The n-type GaN epilayer was grown on sapphire prepared by metal organic chemical vapour deposition and subsequently Co+ ions implanted. The properties of Co+ ions implanted GaN epilayer were investigated by structural and magnetic measurements. The results of Rutherford backscattering spectrometry and channeling illustrate that an excellent crystalline quality (χmin=1.3%) of as-grown GaN. After the implantation of 150 keV Co+ ions with dose 3×1016 cm−2 into GaN and subsequently annealed at 700, 800 and 900 °C, no secondary phase or metal related-peaks were detected by typical XRD. In addition high-resolution X-ray diffraction (HRXRD) was performed to study structural related properties. The magnetization curves were obtained by SQUID and AGM measurements, a well-defined hysteresis loop was observed even at 300 K. The temperature dependence of magnetization was taken in FC and ZFC conditions showed the highest Curie temperature (TC) ∼370 K recorded for Co+ implanted GaN.