Homoepitaxial growth of high-quality GaN nanoarrays for enhanced UV luminescence

Abstract

In this work, we demonstrate the homoepitaxial growth of high-quality GaN nanoarrays on a [0001]-oriented GaN substrate with/without Au catalysts through an accessible chemical vapor deposition process. The morphology observation and structural characterization using scanning electron microscopy and transmission electron microscopy confirm the good alignment and crystallization of GaN nanoarrays, as well as the morphology difference. Further analyses reveal that the GaN nanoarrays have the same [0001] orientation as the underneath GaN film, suggesting homoepitaxial nucleation and growth. In addition, it is also found that the Au catalyst also has a significant impact on the morphology and size modulation of GaN nanoarrays. Room-temperature cathodoluminescence spectra demonstrate the strong near band edge emission in the UV range and the weak yellow-band emission in the visible range, further verifying the improved crystal quality of the GaN nanoarrays through the homoepitaxial growth synthetic strategy due to the superior lattice and thermal matching between the GaN nanoarrays and GaN substrate. All these results suggest that the homoepitaxial approach is extremely efficient for the preparation of high-quality GaN nanostructures toward high-performance optoelectronic nanodevices.