Defect-pit-assisted growth of GaN nanostructures: nanowires, nanorods and nanobelts

Abstract

A new method using defect-pit-assisted growth technology to successfully synthesize the high-quality single crystalline GaN nanostructures by ammoniating Ga₂O₃ films was proposed in this paper. During the ammoniating process, the amorphous middle buffer layer may unavoidably produce some defects and dislocations. Some defect pits come out, which have the lowest surface energy and can subsequently be used as a mask/template or act as potential nucleation sites to fabricate the GaN actinomorphic nanostructures. The as-prepared products are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results indicate that all the reflections of the samples can be indexed to the hexagonal GaN phase and the clear lattice fringes in HRTEM further confirm the growth of high-quality single-crystal GaN nanostructures. The SEM images show that the nanostructures have been realized under different experimental conditions exhibiting different shapes: nanowires, nanorods, and nanobelts. No particles or other nanostructures are found in the SEM study, demonstrating that the product possesses pure nanostructures. These nanostructures show a very good emission peak at 366 nm, which will have a good advantage for applications in laser devices using one-dimensional structures. Finally, the growth mechanism is also briefly discussed.