Кинетика роста планарных нитевидных нанокристаллов

A kinetic equation is obtained which describes the elongation rate of planar semiconductor nanowires growing via the vapor-liquid-solid mechanism in the substrate plane. Theoretical analysis of different regimes depending on the nanowire radius and epitaxial conditions shows that planar growth of nanowires can be limited by either the Gibbs-Thomson effect in a catalyst droplet (for small droplet size) or surface diffusion of adatoms (for larger nanowire radii. Diffusion-like dependence of the growth rate on the nanowire radius R has the form R^(-m), where the power exponent equal 1, 3/2 or 2 depending on the mechanism of surface diffusion transport.

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Kinetics and mechanism of planar nanowire growth

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1911505116 ◽

2019 ◽

Vol 117 (1) ◽

pp. 152-160 ◽

Cited By ~ 4

Author(s):

Amnon Rothman ◽

Vladimir G. Dubrovskii ◽

Ernesto Joselevich

Keyword(s):

Surface Diffusion ◽

Large Scale ◽

Nanowire Growth ◽

Power Exponent ◽

Material Transport ◽

Guided Growth ◽

Large Scale Integration ◽

Scale Integration ◽

And Control ◽

Kinetics Of

Surface-guided growth of planar nanowires offers the possibility to control their position, direction, length, and crystallographic orientation and to enable their large-scale integration into practical devices. However, understanding of and control over planar nanowire growth are still limited. Here, we study theoretically and experimentally the growth kinetics of surface-guided planar nanowires. We present a model that considers different kinetic pathways of material transport into the planar nanowires. Two limiting regimes are established by the Gibbs–Thomson effect for thinner nanowires and by surface diffusion for thicker nanowires. By fitting the experimental data for the length–diameter dependence to the kinetic model, we determine the power exponent, which represents the dimensionality of surface diffusion, and results to be different for planar vs. nonplanar nanowires. Excellent correlation between the model predictions and the data is obtained for surface-guided Au-catalyzed ZnSe and ZnS nanowires growing on both flat and faceted sapphire surfaces. These data are compared with those of nonplanar nanowire growth under similar conditions. The results indicate that, whereas nonplanar growth is usually dominated by surface diffusion of precursor adatoms over the nanowire walls, planar growth is dominated by surface diffusion over the substrate. This mechanism of planar nanowire growth can be extended to a broad range of material–substrate combinations for higher control toward large-scale integration into practical devices.

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Growth and Properties of Silicon Nanowires for Low-Dimensional Devices

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.131-133.535 ◽

2007 ◽

Vol 131-133 ◽

pp. 535-540 ◽

Cited By ~ 2

Author(s):

P. Werner

Keyword(s):

Silicon Nanowires ◽

Molecular Beam ◽

Chemical Vapor ◽

Semiconductor Nanowires ◽

Wetting Layer ◽

Mbe Growth ◽

Active Point ◽

Vapor Liquid Solid Mechanism ◽

Vls Growth ◽

Low Dimensional

The generation of semiconductor nanowires (NWs) by a “bottom-up” approach is of technological interest for the development of new nanodevices. In most cases Si and SiGe nanowires (NWs) are grown by molecular beam epitaxy (MBE) and by chemical vapor deposition (CVD) on the base of the vapor-liquid-solid-mechanism (VLS). In both cases small metal droplets act as a seed for the NW formation. The article mainly refers to the specific features of the MBE growth. The application of metals related to the VLS growth concept (quite often gold droplets are used) also causes several disadvantages of this approach, e.g., the formation of a metal wetting layer on all surfaces, dislocations, and electric active point defects. Concerning the formation of devices, technological steps, such as oxidation and doping of NWs, have to be considered. Specific techniques have to be applied to investigate the properties of individual semiconductor NWs. Some examples shall illustrate this topic.

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A theory of contamination in electron microscopes by surface diffusion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107721 ◽

1978 ◽

Vol 36 (1) ◽

pp. 116-117

Author(s):

J.T. Fourie

Keyword(s):

Electron Beam ◽

Surface Diffusion ◽

High Vacuum ◽

Ultra High Vacuum ◽

Physical Parameters ◽

Carbon Compounds ◽

Hydrocarbon Molecules ◽

Electron Microscopes ◽

Primary Electrons ◽

Long Chain

Contamination in electron microscopes can be a serious problem in STEM or in situations where a number of high resolution micrographs are required of the same area in TEM. In modern instruments the environment around the specimen can be made free of the hydrocarbon molecules, which are responsible for contamination, by means of either ultra-high vacuum or cryo-pumping techniques. However, these techniques are not effective against hydrocarbon molecules adsorbed on the specimen surface before or during its introduction into the microscope. The present paper is concerned with a theory of how certain physical parameters can influence the surface diffusion of these adsorbed molecules into the electron beam where they are deposited in the form of long chain carbon compounds by interaction with the primary electrons.

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