Ferromagnetic properties of (Ga,Mn)N nanowires grown by a chemical vapor deposition method

Ferromagnetic (Ga,Mn)N nanowires were grown on sapphire substrates at 900 °C by a chemical vapor deposition. Synchrotron radiation photoemission spectroscopy revealed that no secondary phases were found in the grown nanowire, meaning the dissolution of Mn atoms to form a solid solution in GaN nanowire. Fermi level was apart by 3.0 eV in the GaN nanowire (n -type), and it shifted toward the valance band maximum with ammonia flow rate. The Ga-to-N ratio decreased with the increase of ammonia flow rate, leading to the increase of Ga vacancies. From this, it is suggested that both increases in magnetic moment and Curie temperature with ammonia flow rate originated from the solid solution of Mn and Ga vacancies.