Electric Field Enhancement Factors Around a Metallic, End-Capped Cylinder

Podenok, S. L.; Sveningsson, Martin; Hansen, Klavs; Campbell, E. E. B.

doi:10.1142/s1793292006000112

Cited by 53 publications

(38 citation statements)

References 19 publications

(20 reference statements)

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“…The modeling results are comparable with those published in the literature (Read & Bowring 2004;Podenok et al 2006). Such modeling points to the possible influence of field enhancement on where nanocrystals are deposited during the ESFDA process.…”

Section: Modeling Of Electric Field Enhancement Along Cnts For Two Casessupporting

confidence: 84%

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Carbon Nanotube-Nanoparticle Hybrid Structures

Chen¹,

Lu²

2010

Carbon Nanotubes

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Section: Modeling Of Electric Field Enhancement Along Cnts For Two Casessupporting

confidence: 84%

“…The vertical CNT was modeled as a cylinder with a hemispherical cap (Read & Bowring 2004;Podenok et al 2006). To simplify the model, a 2-D computational domain with vertical CNT(s) against a flat plane is considered.…”

Section: Modeling Of Electric Field Enhancement Along Cnts For Two Casesmentioning

confidence: 99%

Carbon Nanotube-Nanoparticle Hybrid Structures

Chen¹,

Lu²

2010

Carbon Nanotubes

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“…See Ref. [35] and references therein for more detail. Due to the lack of efficient and compact THz sources and sensors, THz radiation is not as well explored as radiations at other frequencies in the electromagnetic spectrum, and has long been described as the "THz gap".…”

Section: Field Enhancementmentioning

confidence: 99%

“…For a hemisphere-capped cylinder of length L and radius R in a static field, γ is approximately proportional to ∼ L/R [35]. However, in the presence of THz radiation of wavelength λ, retardation effects will limit the effective length of the emitter to Chapter 5.…”

Section: Chapter 5 High-energy Electron Emission From Metallic Nano-mentioning

confidence: 99%

“…Specifically, approximate analytic forms for both the time-dependent tunneling probability and the spatial distribution of the enhanced field are used to compute the energy distributions of the detected electrons for 1-dimensional motion along the tip axis, z. Rather than attempting to precisely model the geometry of the tips and compute the enhanced field via finite-difference techniques, we employ a generalized form for the field enhancement factor at the tip apex [35], γ = β(λ/R) α , where β and α are constants to be determined. The FowlerNordheim tunneling formula [28] is used to compute the rate at which electrons are emitted (with zero initial energy) into the enhanced field.…”

Section: Chapter 5 High-energy Electron Emission From Metallic Nano-mentioning

confidence: 99%

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Field Ionization and Field Emission with Intense Single-cycle THz Pulses

Li¹

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This dissertation focuses on light-matter interactions in the strong-field, lowfrequency, single-cycle regime in both gas-phase and solid-state systems through the investigation of field ionization of Rydberg atoms and field emission from metallic nano-tips exposed to intense, single-cycle THz pulses. Field ionization/emission mechanism, as well as post-ionization/emission energy transfer dynamics, have been studied.In the experiments, single-cycle THz pulses with a central frequency f ∼0.2 THz and peak field amplitude F m ∼0.5 MV/cm are used to explore: 1) Field ionization of excited atoms (Na Rydberg states of nd, n = 6−15) in the long-pulse/low-frequency regime. A F ∝ n −3 over-the-barrier ionization threshold scaling behavior is observed, reflecting the suppression of core-scattering during the ionization pulse and, more importantly, the extended times required for Rydberg electrons to escape over the field-dressed Coulomb potential barrier. We have also examined energy transfer in the single-cycle limit and showed that in contrast to ionization by multi-cycle pulses, electrons that are ionized near the field extrema of a single-cycle pulse acquire substantial energies (∼ 2U p ), and those ionized near the zero-crossing can obtain much larger energies (> 6U p ), even in the absence of rescattering.2) Field ionization of oriented atoms (Na Rydberg-Stark states in an n-manifold, n = 10−12). The ionization threshold fields are found to be orientation-dependent, due to both diabatic population transfer between "uphill" and "downhill" oriented states and an asymmetry in the single-cycle THz waveform.3) High-energy field-electron-emission from W nano-tips having different cone angles and tip radii, 10 nm < R < 1 µm. Electrons with energies easily exceeding iii 5 keV are observed. The maximum electron energies are proportional to the peak THz field and are roughly independent of the tip radius. These observations can be attributed to the large field enhancement and spatial localization of the enhanced field in the vicinity of the nano-tips. At low-frequencies/long-wavelengths, such near-field characteristics can fundamentally change the energy transfer process as compared to that which occurs following the ionization of gas-phase atoms or molecules, and allow for the creation of very high energy electrons.iv

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Theory for hierarchical assembly with dielectrophoresis and the role of particle anisotropy

Cao

Brown

2020

Electrophoresis

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Nonuniform electric fields cause polarizable particles to move through an effect known as dielectrophoresis (DEP). Additionally, the particles themselves create nonuniform fields due to their induced dipoles. When the nonuniform field of one particle causes another to move, it represents a path to hierarchical assembly termed mutual DEP (mDEP). Anisotropic particles potentially provide further opportunities for assembly through intense and intricate local field profiles. Here, we construct a theoretical framework for describing anisotropic particles as templates for assembly through mDEP by considering the motion of small nanoparticles near larger anisotropic nanoparticles. Using finite element analysis, we study eight particle shapes and compute their field enhancement and polarizability in an orientation‐specific manner. Strikingly, we find a more than tenfold enhancement in the field near certain particle shapes, potentially promoting mDEP. To more directly relate the field intensity to the anticipated assembly outcome, we compute the volume experiencing each field enhancement versus particle shape and orientation. Finally, we provide a framework for predicting how mixtures of two distinct particle species will begin to assemble in a manner that allows for the identification of conditions that kinetically bias assembly toward specific hierarchical outcomes.

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Electric Field Enhancement Factors Around a Metallic, End-Capped Cylinder

Cited by 53 publications

References 19 publications

Carbon Nanotube-Nanoparticle Hybrid Structures

Carbon Nanotube-Nanoparticle Hybrid Structures

Field Ionization and Field Emission with Intense Single-cycle THz Pulses

Theory for hierarchical assembly with dielectrophoresis and the role of particle anisotropy

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