Nanodimensional whisker growth by the generalized vapor-liquid-crystal mechanism

Possible VLS (Vapor-Liquid-Solid) whisker growth has been discovered for the first time in nature on the surface of lunar breccia 15015. Rock 15015 was collected on the Apollo 15 flight and is blocky, angular, largely glass-covered, almost 30 cm long and weighs 4.5 kg. A 62 mm2 glass-covered surface of a fragment of 15015 (15015,36) was coated with 150 Å of Au and selected areas studied in detail with a JEOLCO JSM-1 scanning electron microscope (SEM), an ARL scanning electron microprobe (EMX SM) with a QANTA/METRIX energy dispersive spectrophotometer and a Cambridge MK IIA SEM at Texas Instruments, Inc. of Dallas.

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Development of Growth Theory for Vapor–Liquid–Solid Nanowires: Wetting Scenario, Front Curvature, Growth Angle, Linear Tension, and Radial Instability

Journal of Nanotechnology ◽

10.1155/2020/5251823 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Valery A. Nebol’sin ◽

Nada Swaikat ◽

Alexander Yu. Vorob’ev

Keyword(s):

Liquid Crystal ◽

Size Dependence ◽

Droplet Surface ◽

Catalyst Droplet ◽

Linear Tension ◽

Growth Angle ◽

Stable Conditions ◽

Three Phase ◽

Curvature Growth ◽

Vapor Liquid

In this paper, we report that under wetting conditions (or modes) of nanowire (NW) growth, when a nonplanar crystallization front emerges under a catalyst droplet, a shift in the three-phase line (TPL) of the vapor–liquid–crystal interface occurs under thermodynamically stable conditions when the angle with respect to the droplet surface, termed the growth angle, is fixed. The growth angle of the NWs is determined not from a geometrical perspective but on the basis of the physical aspects of the processes occurring around the TPL, revealing a size dependence caused by the influence of linear tension of the three-phase contact of a vapor–liquid crystal. The observed radial periodic instability of the NWs is described according to the size dependence of the thermodynamic growth angle, which induces negative feedback in the system. Under the influence of linear tension and positive feedback, the tips or needles of NWs can be formed.

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Effect of Sn for the dislocation-free SiSn nanostructure formation on the vapor-liquid-crystal mechanism

AIP Advances ◽

10.1063/1.5139936 ◽

2020 ◽

Vol 10 (1) ◽

pp. 015309 ◽

Cited By ~ 1

Author(s):

Vyacheslav Timofeev ◽

Vladimir Mashanov ◽

Alexander Nikiforov ◽

Ilya Skvortsov ◽

Tatyana Gavrilova ◽

...

Keyword(s):

Liquid Crystal ◽

Nanostructure Formation ◽

Vapor Liquid

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Freeze-fracture TEM of the helical smectic A* phase

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012179x ◽

1992 ◽

Vol 50 (1) ◽

pp. 278-279

Author(s):

K.J. Ihn ◽

R. Pindak ◽

J. A. N. Zasadzinski

Keyword(s):

Liquid Crystal ◽

Grain Boundary ◽

Grain Boundaries ◽

Freeze Fracture ◽

Smectic Phase ◽

Layer Spacing ◽

Screw Dislocations ◽

Smectic A ◽

Smectic Phases ◽

Discrete Amount

A new liquid crystal (called the smectic-A* phase) that combines cholesteric twist and smectic layering was a surprise as smectic phases preclude twist distortions. However, the twist grain boundary (TGB) model of Renn and Lubensky predicted a defect-mediated smectic phase that incorporates cholesteric twist by a lattice of screw dislocations. The TGB model for the liquid crystal analog of the Abrikosov phase of superconductors consists of regularly spaced grain boundaries of screw dislocations, parallel to each other within the grain boundary, but rotated by a fixed angle with respect to adjacent grain boundaries. The dislocations divide the layers into blocks which rotate by a discrete amount, Δθ, given by the ratio of the layer spacing, d, to the distance between grain boundaries, lb; Δθ ≈ d/lb (Fig. 1).

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