Catalyst-Directed Crystallographic Orientation Control of GaN Nanowire Growth
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- 作者：Tevye R. Kuykendall ; M. Virginia P. Altoe ; D. Frank Ogletree ; Shaul Aloni
- 刊名：Nano Letters
- 出版年：2014
- 出版时间：December 10, 2014
- 年：2014
- 卷：14
- 期：12
- 页码：6767-6773
- 全文大小：538K
- ISSN：1530-6992
文摘
In this work, we demonstrate that catalyst composition can be used to direct the crystallographic growth axis of GaN nanowires. By adjusting the ratio of gold to nickel in a bimetallic catalyst, we achieved selective growth of dense, uniform nanowire arrays along two nonpolar directions. A gold-rich catalyst resulted in single-crystalline nanowire growth along the 鉄?1虆00鉄?or m axis, whereas a nickel-rich catalyst resulted in nanowire growth along the 鉄?12虆0鉄?or a axis. The same growth control was demonstrated on two different epitaxial substrates. Using proper conditions, many of the nanowires were observed to switch direction midgrowth, resulting in monolithic single-crystal structures with segments of two distinct orientations. Cathodoluminescence spectra revealed significant differences in the optical properties of these nanowire segments, which we attribute to the electronic structures of their semipolar {112虆2} or {11虆01} sidewalls.