Characterization of n-GaN dilute magnetic semiconductors by cobalt ions implantation at high-fluence

Abstract

In this study, we present the structural and magnetic characteristics of cobalt ions implantation at a high-fluence (5×1016cm−2) into n-GaN epilayer of thickness about 1.6μm. The n-GaN was grown on sapphire by metal organic chemical vapor deposition (MOCVD). Rutherford backscattering channeling was used for the structural study. After implantation, samples were annealed at 700, 800 and 900°C by rapid thermal annealing in ambient N2. XRD measurements did not show any secondary phase or metal related-peaks. High resolution X-ray diffraction (HRXRD) was performed as well to characterize structures. Well-defined hysteresis loops were observed at 5K and room temperature using alternating gradient magnetometer AGM and Superconducting Quantum Interference Device (SQUID) magnetometer. Temperature-dependent magnetization indicated magnetic moment at the lowest temperatures and retained magnetization up to 380K for cobalt-ion-implanted samples.