Kinetically Induced Kinking of Vapor−Liquid−Solid Grown Epitaxial Si Nanowires

Abstract

Epitaxial Si nanowires grown from Au seeds using the vapor-liquid-solid method begin growing normal to the Si(111) substrate atop a tapered base. After a kinetically determined length, the NWs may kink away from [111] to another crystallographic direction. The smallest NWs prefer growth along 110 while larger Si NWs choose either 111 or 112 based on whether growth conditions favor Au-free sidewalls. "Vertical" growth normal to the Si(111) substrate is obtained only for slowly growing NWs with Au-decorated sidewalls. At the fastest growth rates, single-crystal Si NWs smoothly, continuously, and randomly vary their growth directions, producing a morphology that is qualitatively different than highly kinked growth.

Molecular dynamics simulations of gold-catalyzed growth of silicon bulk crystals and nanowires

“…2 in the surface morphology of the crystals is that the top NW surface becomes curved near the edges for both {111} and {110} orientations. This is consistent with transmission electron microscopy observations 12 and earlier predictions from continuum models. 27 …”

“…11 What causes growth anomalies such as kinking (i.e., sudden change of NW orientation during growth) ? 12 What is responsible for the formation of metastable phases, such as hexagonal close-packed Au, 13 upon growth termination? Answering these questions requires an understanding of the NW nucleation and growth mechanisms at the atomistic level.…”

Atomistics of vapour–liquid–solid nanowire growth

“…The technique was demonstrated successfully in the 1960s in the context of crystalline whisker growth2, and has become increasingly relevant of late as it offers direct control over nanowire composition and morphology, aspects of critical importance in several nanowire-based applications8910111213141516171819. The salient features can be readily seen in the schematic illustration in Fig.…”

Diameter-Controlled Solid-Phase Seeding of Germanium Nanowires: Structural Characterization and Electrical Transport Properties

“…The observed growth directions, determined by the corresponding FFT pattern of the HRTEM images, are displayed in figure S2 (see Supporting Information) for the Ge nanowires grown from the Ni nanocrystals. For Ge nanowire diameters below 20 nm [26,27] the <110> orientation of the Ge crystals was predominant (>75 %), with minor quantities of <211> and <111> also being present. The observation of a preferred <110> growth direction differs from data previously reported for Ni-seeded Ge nanowires grown under supercritical conditions, which described a similar quantity of <111> and <110> oriented Ge crystals [21].…”