Synthesis And Characterization Of Transition Metal Elements Doped GaN Nanostructures

GaN can be converted to be ferromagnetic from the nature of the diamagnetic by nanosized or chemical doping technical means. GaN based diluted magnetic semiconductors(DMSs) have excellent optical, magnetic and electrical properties for applications in the fabrications of advanced magnetic and optoelectric devices.Sm doped GaN nanowires were synthesized via chemical vapor deposition method. The XRD patterns evidence that the GaN samples are wurtzite structure. The SEM analyses indcate that the length to diameter ratio of GaN nanowires can be up to 400:1, and their well-crystallized single crystal nature are proved by HRTEM and SAED. The EDX line-scanning and mapping patterns show that Sm atoms are distributed uniformly in GaN nanowires. Magnetic measurement results at room temperature suggest that samples exhibit ferromagnetic order, which is mainly attributed to the introduction of Sm atoms in GaN.Sm doped GaN powders were synthesized by a direct nitridation method. The XRD patterns reveal that the GaN samples are wurtzite structure. The doping treatment make the products have smaller the average particle size of less than 100 nm and lead to a blue shift 8 nm of near the band edge emission. The samples doped with Sm have more widely ranges of temperature in the fixed dielectric constant and dielectric loss than that of pure GaN sample and have lower rate of increase of the parameters with the increase of temperature.The morphologies of GaN nanostructures can be tuned with the addition of MoCl5 by chemical vapor deposition. The radial dimension of the GaN nanowire reduces, and the axial dimension increases with the increasing of MoCl5 concentration gradually. When the amount of MoCl5 concentration is 10%, the morphology of GaN nanowires are straight with an average diameter of 50 nm and length more than 100 μm. However, when the concentration of MoCl5 increases to 15%, the zigzag and spiral nanostructures are obtained. Continuing to increase the concentration of MoCl5, the morphology of samples converts to two-dimensional or three-dimensional structures.