Fabrication of vertical GaN/InGaN heterostructure nanowires using Ni-Au bi-metal catalysts

Abstract

We have fabricated the vertically aligned coaxial or longitudinal heterostructure GaN/InGaN nanowires. The GaN nanowires are first vertically grown by vapor–liquid-solid mechanism using Au/Ni bi-metal catalysts. The GaN nanowires are single crystal grown in the [0001] direction, with a length and diameter of 1 to 10 μm and 100 nm, respectively. The vertical GaN/InGaN coaxial heterostructure nanowires (COHN) are then fabricated by the subsequent deposition of 2 nm of InxGa1-xN shell on the surface of GaN nanowires. The vertical GaN/InGaN longitudinal heterostructure nanowires (LOHN) are also fabricated by subsequent growth of an InGaN layer on the vertically aligned GaN nanowires using the catalyst. The photoluminescence from the COHN and LOHN indicates that the optical properties of GaN nanowires can be tuned by the formation of a coaxial or longitudinal InGaN layer. Our study demonstrates that the bi-metal catalysts are useful for growing vertical as well as heterostructure GaN nanowires. These vertically aligned GaN/InGaN heterostructure nanowires may be useful for the development of high-performance optoelectronic devices.

Formation of island arrays by melting of Bi, Pb and Sn continuous films on Si substrate

“…The obtained correlations (Table 1) between the island radius and the film thickness (R = 6.3t at = 114 • for Bi and R = 2.2t at = 127 • for Sn) agree well with expression (2). However, if one considers only the values of the wetting angles, then the relations R = 2.1t for Bi and R = 1.9t for Sn are obtained, that is, the difference of the factors of proportionality between R and t for Bi and Sn is insignificant.…”

“…But, on the other hand, an array of already formed islands on the substrate is interesting in itself in terms of practical use. For example, such arrays are used in catalysis [2], biosensors [3], information storage [4] and optics and photonics [5]. However, for practical use, one needs nanoarrays consisting of particles of almost the same size.…”

Metal-seeded growth of III–V semiconductor nanowires: towards gold-free synthesis

“…152 Extensive analysis of the growth process and composition of this system has been performed, and it is generally accepted that the Ni seed particles have a solid phase during nanowire growth. 156,157 Several recent reports have also shown the growth of GaN and GaN-InGaN heterostructure nanowires using Au-Ni alloy particles, 158,159 representing some of the rst attempts to grow III-V nanowires with particles containing two foreign metals. The authors report that formation of epitaxially-aligned nanowires is easier with alloy particles than with pure Ni, and attribute the difference to faster nucleation with the addition of gold.…”

Circumventing the miscibility gap in InGaN nanowires emitting from blue to red

“…Although there have been fewer results reported on the growth of In x Ga 1−x N nanowires by MOCVD, the observed trends are qualitatively the same-more In x Ga 1−x N/GaN heterostructures have been synthesized [37][38][39][40][41][42][43][44][45][46][47][48][49][50] compared to nanowires composed exclusively of In x Ga 1−x N [51][52][53][54][55]. As a matter of fact, MOCVD method has demonstrated its potential for the growth of radial In x Ga 1−x N/GaN heterostructures, but their PL emission peak does not exceed 550 nm [40].…”