Room Temperature Ferromagnetism in Si-Doped GaN Powders

Un-doped and Si-doped GaN powders were prepared by direct nitridation of Ga2O3 under NH3 atmosphere. Energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoemission spectroscopy indicate that Si atoms are successfully incorporated into GaN lattices and substitute for Ga atoms. Scanning electron microscopy, Raman scattering and photoluminescence demonstrate that the Si doping results in the decrease of crystalline sizes and the increase of defects in the samples. The room temperature ferromagnetism is observed in the Ga1-xSixN powders which is enhanced with increasing Si content. It is proposed that the defects, oxygen impurity and Si dopants play important roles to determine the long-range magnetic order in the Si-doped GaN powders.