Crystallographic orientation control and optical properties of GaN nanowires

Abstract

The optical and electrical properties of nitride materials are closely related to their crystallographic orientation. Here, we report our effort on crystallographic orientation manipulation of GaN NWs using vapour-liquid-solid hydride vapour phase epitaxy (VLS-HVPE). The growth orientations of the GaN NWs are tuned from the polar c-axis to the non-polar m-axis by simply varying the supply of III precursors on various substrates, including c-, r, m-plane sapphire, (111) silicon and (0001) GaN. By varying the size of the Ni/Au catalyst, we found that the catalyst size has a negligible influence on the growth orientation of GaN NWs. All these demonstrate that the growth orientation of the GaN NWs is dominated by the flow rate of the precursor, regardless of the catalyst size and the substrate adopted. Moreover, the optical properties of GaN NWs were characterized using micro-photoluminescence, revealing that the observed red luminescence band (near 660 nm) is related to the lateral growth of the GaN NWs. The work presented here will advance the understanding of the VLS process of GaN NWs and represents a step forward towards controllable GaN NW growth.

Epitaxial growth of 1D GaN-based heterostructures on various substrates for photonic and energy applications

“…The GaN NWs have lengths of 3 ± 0.2 mm, diameters of 48 ± 10 nm, and densities of 8 ± 0.5 10 8 cm −2 . Because it is widely known that the growth direction of GaN core NW can be modied by optimizing the supply of precursors, 86 the growth direction is optimized utilizing a nely regulated supply of gallium and nitrogen precursors. It is evident that the growth on top of the glass substrate is homogeneous.…”

GaN Nanowire Growth Promoted by In–Ga–Au Alloy Catalyst with Emphasis on Agglomeration Temperature and In Composition

“…It is a real fact that the growth of NWs can be optimized using different metal catalysts with the careful investigation of agglomeration behavior of liquid metal droplets. Change in crystallographic orientation has been attributed to the choice of substrate or change in the V–III ratio. , To the best of our knowledge, there are a few reports on the crystallographic orientation control of NWs by varying the catalyst composition. , Kuykendall et al achieved the selective growth of GaN NWs along two nonpolar directions by adjusting the ratio of gold to nickel in the catalyst . Regarding the crystallographic orientation of the NWs, Joyce et al proposed a model to control the crystallographic orientation of the GaN NWs by varying the temperature and V/III ratio .…”

“…Change in crystallographic orientation has been attributed to the choice of substrate or change in the V−III ratio. 27,28 To the best of our knowledge, there are a few reports on the crystallographic orientation control of NWs by varying the catalyst composition. 29,30 Kuykendall et al achieved the selective growth of GaN NWs along two nonpolar directions by adjusting the ratio of gold to nickel in the catalyst.…”

Direct Growth of AlGaN Nanorod LEDs on Graphene-Covered Si

“…Zhuang et al [7] developed a soft UV-curing nanoimprint lithography (NIL) technique for fabricating GaN nanogratings and nanorods, followed by reactive ion etching (RIE) and inductively coupled plasma (ICP) system processes. Our group also reported the controlled growth of GaN nanowires by a metal-catalyzed method using hydride vapor phase epitaxy (HVPE) system and achieved the orientation-controllable GaN nanowires with a high aspect ratio and excellent crystal quality [8,9].…”