Role of liquid droplet surface diffusion in the vapor-liquid-solid whisker growth mechanism

Wang, Hongyu; Fischman, Gary S.

doi:10.1063/1.358515

Cited by 52 publications

(42 citation statements)

References 30 publications

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“…The essential steps of the VLS mechanism are [41][42][43]: (i) mass transport of the vapor components in the gas phase to the vapor-liquid interface; (ii) chemical reaction on the vaporliquid interface; (iii) dissolution into and diffusion through the liquid phase. The surface of the liquid droplet might also serve as a favorable mass transport path for nanowire growth [44]; (iv) precipitation on the liquid-solid interface and subsequent incorporation into the growing wire lattice according to some two-dimensional growth mechanism.…”

Section: Growth Mechanism Of the Nanowiresmentioning

confidence: 99%

Nanowires for surface enlargement of narrow‐bore fused‐silica tubing

Woldegiorgis¹,

Jansson²,

Curcio³

et al. 2004

Electrophoresis

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A method for preparation of silica nanowires with dimensions of d = 10-100 nm, l = 5-500 nm, is described. The nanostructured material is an integral part of the inner surface of narrow bore fused-silica capillary tubing. The wire preparation method is based on a decomposition of 2-chloro-1,1,2-trifluoroethyl methyl ether at elevated temperature and pressure. The silica bulk material is rearranged via a sustained silica-hydrogen fluoride chemistry, and reaction mechanisms for this process are proposed. The method is suitable for preparing long lengths of tubing with the modified surface. It is our belief that the texture of the capillary wall with its increased surface area is useful for applications such as microreactions, catalysis, and high-resolution pressure and/or electrodriven open-tubular liquid chromatography.

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Section: Growth Mechanism Of the Nanowiresmentioning

confidence: 99%

Nanowires for surface enlargement of narrow‐bore fused‐silica tubing

Woldegiorgis¹,

Jansson²,

Curcio³

et al. 2004

Electrophoresis

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“…6,9 In those diffusion-dominated VLS models, precursors from the vapor phase first land on the surface of the catalyst droplet and then diffuse via hopping of individual atoms across the surface or through the bulk. 10,11 Thus, the nanowire growth rate hangs on the concentration gradient and diffusion coefficient of the precursor elements. Surface diffusion generally dominates the growth process in the cases of small droplet, poor solubility of growth species in catalyst, and large ratio of surface-to bulk diffusion coefficient.…”

Section: Introductionmentioning

confidence: 99%

“…Surface diffusion generally dominates the growth process in the cases of small droplet, poor solubility of growth species in catalyst, and large ratio of surface-to bulk diffusion coefficient. 10 Mass transport via surface can lead to a larger growth rate, thus favorable for the fast production of nanowires.…”

Section: Introductionmentioning

confidence: 99%

“…Any method that allows accessing the intervening processes in a particular circumstance helps improve the understanding of this mechanism. Furthermore, the catalyst particles involved in VLS growth are often actualized via agglomeration from a pre-deposited film, 10,13 which requires a good wettability of the catalyst metal to substrate. The assembly of catalyst particles from a pre-deposited film also intermingles with the rooting of the nanowires, causing some additional difficulties to the implementation of the VLS mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Fast vapor phase growth of SiO2 nanowires via surface-flow on Ag core/SiO2 shell structure

Gao

et al. 2012

AIP Advances

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Uniform, millimeter-long SiO2 nanowires were grown from co-evaporation of Ag2O and SiO powders. The ‘frozen’ growth scenario by cooling enables revelation of the vapor-liquid-solid mechanism here in action, which is generally inaccessible due to the high temperature and high pressure condition. Ag core/SiO2 shell preformed in the vapor and wetting the substrate will expose its liquid Ag-core to catalyze nanowire growth, at a rate over 10 nm/s, via viscous flow of the encasing SiO2 layer which precipitates through a liquid neck zone. This method is characteristic of high-yield of catalytic seeds free from overgrowth or consuming, easy control of wire thickness by vapor pressure adjustment, enhanced rooting ability since catalyst deposition on substrate becomes dispensable, etc. Also spinning growth of nanowires observed in many other circumstances can be explained by the viscous flow mechanism.

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“…The growth rate is mainly determined by the diffusion of Si along the surface of the liquid-alloy droplet rather than by the diffu- sion of Si in the bulk. [31] As far as this liquid droplet is concerned, there is a well-known equation…”

mentioning

confidence: 99%

Controllable Synthesis and Growth Model of Amorphous Silicon Nanotubes with Periodically Dome‐Shaped Interiors

Liu

et al. 2006

Advanced Materials

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strate rotation, x sub , was related to the deposition rate, r, and the pitch of the film, p, as follows: p = r/x sub . Deposition rates were in the range 5-15 Å s -1 . Samples on both the silicon and glass substrates were cleaved using a diamond scribe prior to SEM imaging.Transmission Ellipsometry: A variable-angle spectroscopic ellipsometer (VASE, J. A. Woollam, Inc.) used in transmission mode was used to measure the transmission of p-and s-polarized light through the samples deposited on glass, and also to measure the transmission Mueller matrix of these samples, with the m 11 coefficient normalized to 1 at all wavelengths. Scans were performed in the wavelength range 400-700 nm. The transmission of p-and s-polarized light was averaged to determine the un-normalized m 11 (k) element of the Mueller matrix, which was used in combination with the m 14 (k) element to determine the selective transmission for the samples.Photoluminescence Detection: The photoluminescence response of the films was measured using the 365 nm emission line of a mercury lamp (Hamamatsu LightningCure L8333) for excitation and a spectrometer (Ocean Optics USB2000) for detection. The excitation light was focused onto a 5 mm by 5 mm square region. The polarization emitted for the helical films was measured by placing a quarter waveplate and a Glan-Taylor polarizer between the sample and the spectrometer for the helical films, with the fast axis of the waveplate oriented at ±45°to the polarizing axis. The orientation of the polarizer was kept constant with respect to the spectrometer grating, in order to eliminate the polarization sensitivity of the detector. The dense reference film was also tested in this setup and showed identical photoluminescence spectra, and thus a null dissymmetry factor spectrum, for both left-and right-handed emission.

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Role of liquid droplet surface diffusion in the vapor-liquid-solid whisker growth mechanism

Cited by 52 publications

References 30 publications

Nanowires for surface enlargement of narrow‐bore fused‐silica tubing

Nanowires for surface enlargement of narrow‐bore fused‐silica tubing

Fast vapor phase growth of SiO2 nanowires via surface-flow on Ag core/SiO2 shell structure

Controllable Synthesis and Growth Model of Amorphous Silicon Nanotubes with Periodically Dome‐Shaped Interiors

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