Site-Controlled VLS Growth of Planar Nanowires: Yield and Mechanism

Abstract

The recently emerged selective lateral epitaxy of semiconductor planar nanowires (NWs) via the vapor-liquid-solid (VLS) mechanism has redefined the long-standing symbolic image of VLS NW growth. The in-plane geometry and self-aligned nature make these planar NWs completely compatible with large scale manufacturing of NW-based integrated nanoelectronics. Here, we report on the realization of perfectly site-controlled growth of GaAs planar NW arrays with unity yield using lithographically defined gold (Au) seed dots. The growth rate of the planar NWs is found to decrease with the NW width at fixed spacing, which is consistent with the conventional VLS model based on the Gibbs-Thomson effect. It is found that in general, the planar and out-of-plane NW growth modes are both present. The yield of planar NWs decreases as their lateral dimension shrinks, and 100% yield of planar NWs can be achieved at moderate V/III ratios. Based on a study of the shape of seed particles, it is proposed that the adhesion between the liquid-phase seed particle and the substrate surface is important in determining the choice of growth mode. These studies represent advances in the fundamental understanding of the VLS planar NW growth mechanism and in the precise control of the planar NW site, density, width, and length for practical applications. In addition, high quality planar InAs NWs on GaAs (100) substrates is realized, verifying that the planar VLS growth mode can be extended to heteroepitaxy.

Surface effects of vapour-liquid-solid driven Bi surface droplets formed during molecular-beam-epitaxy of GaAsBi

“…Thus, ± is the bi-direction we assign to our nanotracks. This directional assignment agrees well with other reports of self-aligned planar growths63646566. Figure 5(c) shows how lateral motion in the ± directions is achieved by this process; the formation of a flexible liquid surface at the liquid-solid interface facilitates preferential growth away from the c -axis, with the droplet motion restricted in-plane.…”

Ag nanoparticle catalyst based on Ga2O3/GaAs semiconductor nanowire growth by VLS method

“…During past decades, the semiconductor nanowire (NWs) has been interest due to their potential in low dimension such as nano science, nano material and nanotechnology [1][2][3][4][5]. Due to their low dimension properties, that they are controllable, tunable conductivity, variable and diameter dependent band gap, flexible surface chemistry, large surface e area, enhanced exciton binding energy, and increased surface scattering for electrons and phonons, etc.…”

“…Especially, the Ga 2 O 3 /GaAs NW growth have attracted substantial attention for various applications on nanoelectronics, optoelectronics, and nanosensors, etc. [3][4][5][6], as well as the Ga 2 O 3 /GaAs NWs growth will expect many exciting opportunities on nanoscale science and technology [7][8][9][10].…”

Mechanism of periodic height variations along self-aligned VLS-grown planar nanostructures

“…This bi-directional growth facet agrees well with the literature. 25,30,31,36 That we see equal movement in opposite directions eliminates thermal gradient or electric field effects underpinning this preference. The typical details of the nanotrack morphology are contained in the AFM data shown in Fig.…”

“…19,[26][27][28][29] Nanowires which self-align on the surface could play an important role in combining the synthesis and assembly in a single step, while offering compatibility with traditional planar device structures. 25,[28][29][30][31] In this paper, we extend the current palette of non-monotonous one-dimensional nanostructures and investigate a new type of self-aligned GaAsBi planar nanotrack exhibiting periodic changes in height along its full length. We find that an explanation for this unusual shape is outside the capacity of existing planar nanowire growth models 19,25 and develop a a Institute for Superconducting and Electronic Materials and School of Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia.. E-mail: js598@uowmail.edu.au more pertinent semi-empirical growth model -one that accounts for the localized adsorption of species on the droplet surface and connects them to a functional describing the rate of nucleation across an inhomogeneous liquid-solid growth interface.…”