A Study on Self-Assembled GaN Nanobelts by a New Method: Structure, Morphology, Composition, and Luminescence

A new method using two-step growth technology to successfully synthesize high-quality single crystalline GaN nanobelts was employed in this paper. This growth method is applicable to continuous synthesis and able to produce a large number of single-crystalline GaN nanobelts with a relatively high purity and at a low cost. The results of X-ray diffraction (XRD) and selective area electron diffraction (SAED) patterns indicate that the reflections of the samples can be indexed to the hexagonal GaN phase with single crystal structure. From the scanned electron microscopy (SEM) morphology, we can see that the width of the nanobelts is about 800 nm, and the ratio of thickness to width is about 1/10. The maximum length is up to several tens of micrometers. No particles or other nanostructures are found in the SEM observation, demonstrating that the product possesses pure nanobelts. In the high-resolution transmission electron microscopy (HRTEM) image, the clear lattice fringes indicate the growth of high-quality single-crystal GaN nanobelts. X-ray photoelectron spectroscopy (XPS) confirms the formation of bonding between Ga and N, and yields the surface stoichiometry of Ga:N of about 1:1.03. The representative photoluminescence spectrum exhibits a strong emission peak at 369.3 nm and four weak emission peaks. Finally, the growth mechanism is also briefly discussed.