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van Dorp WF. The role of electron scattering in electron-induced surface chemistry. Phys Chem Chem Phys 2012; 14:16753-9. [DOI: 10.1039/c2cp42275a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sychugov I, Nakayama Y, Mitsuishi K. Manifold enhancement of electron beam induced deposition rate at grazing incidence. NANOTECHNOLOGY 2010; 21:025303. [PMID: 19955608 DOI: 10.1088/0957-4484/21/2/025303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
It is shown how a significant drawback of the electron beam induced deposition technique, namely its low deposition rate, can be circumvented. By tilting a sample, a larger part of the primary electron beam energy becomes dissipated closer to the interface. This in turn increases the emission of secondary electrons, largely responsible for the deposition of the adsorbed molecule components on the surface. An order of magnitude increase in the deposition rate is reported in the fabrication of metal nanowires from organic precursor gas.
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Affiliation(s)
- Ilya Sychugov
- Quantum Dot Research Center, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
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Moskalenko AV, Gordeev SN, Koentjoro OF, Raithby PR, French RW, Marken F, Savel'ev S. Fabrication of shuttle-junctions for nanomechanical transfer of electrons. NANOTECHNOLOGY 2009; 20:485202. [PMID: 19887707 DOI: 10.1088/0957-4484/20/48/485202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on the fabrication of nanomechanical devices for shuttling of electrons from one electrode to another. Each device consists of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes. In two different kinds of shuttle-junctions the nanoparticle is attached to the electrodes through either (i) a single layer of 1,8-octanedithiol or (ii) a multilayer of 1-octanethiol molecules. The thiol layers play the role of 'damped springs', such that when a sufficient voltage bias is applied to the junction, the nanoparticle is expected to start oscillating and thereby transferring electrons from one electrode to the other. For both kinds of shuttle-junctions we observed an abrupt increase in the transmitted current above a threshold voltage, which can be attributed to a transition from the stationary to the oscillating regime. The threshold voltage was found to be lower for single-layer shuttle-junctions.
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Affiliation(s)
- A V Moskalenko
- Department of Physics, University of Bath, Claverton Down Road, Bath BA27AS, UK.
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Botman A, Mulders JJL, Hagen CW. Creating pure nanostructures from electron-beam-induced deposition using purification techniques: a technology perspective. NANOTECHNOLOGY 2009; 20:372001. [PMID: 19706953 DOI: 10.1088/0957-4484/20/37/372001] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The creation of functional nanostructures by electron-beam-induced deposition (EBID) is becoming more widespread. The benefits of the technology include fast 'point-and-shoot' creation of three-dimensional nanostructures at predefined locations directly within a scanning electron microscope. One significant drawback to date has been the low purity level of the deposition. This has two independent causes: (1) partial or incomplete decomposition of the precursor molecule and (2) contamination from the residual chamber gas. This frequently limits the functionality of the structure, hence it is desirable to improve the decomposition and prevent the inclusion of contaminants. In this contribution we review and compare for the first time all the techniques specifically aimed at purifying the as-deposited impure EBID structures. Despite incomplete and scattered data, we observe some general trends: application of heat (during or after deposition) is usually beneficial to some extent; working in a favorable residual gas (ultra-high vacuum set-ups or plasma cleaning the chamber) is highly recommended; gas mixing approaches are extremely variable and not always reproducible between research groups; and carbon-free precursors are promising but tend to result in oxygen being the contaminant species rather than carbon. Finally we highlight a few novel approaches.
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Affiliation(s)
- A Botman
- Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
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Lassiter MG, Rack PD. Nanoscale electron beam induced etching: a continuum model that correlates the etch profile to the experimental parameters. NANOTECHNOLOGY 2008; 19:455306. [PMID: 21832771 DOI: 10.1088/0957-4484/19/45/455306] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper, we relate experimental electron beam induced etching profiles to various electron limited and mass transport limited regimes via a continuum model. In particular, we develop a series of models with increasing complexity and demonstrate the effects and interactions that the precursor gas adsorption kinetics, the electron flux distribution, and the etch product desorption kinetics have on the resultant nanoscale etching profile. Unlike analogous electron beam induced deposition models, it is shown that one must consider the diffusion, desorption, and possible re-dissociation of the resultant etch product to understand the observed etching profiles. To confirm the explanation of the etch results, a defocus experiment was performed showing transitions from the electron flux limited to the mass transport limited to the etch product dissociation limited regimes.
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Affiliation(s)
- Matthew G Lassiter
- University of Tennessee, 308 Dougherty Engineering Hall, Knoxville, TN 37996, USA
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Smith DA, Fowlkes JD, Rack PD. Simulating the effects of surface diffusion on electron beam induced deposition via a three-dimensional Monte Carlo simulation. NANOTECHNOLOGY 2008; 19:415704. [PMID: 21832655 DOI: 10.1088/0957-4484/19/41/415704] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The effects that adsorbed precursor surface diffusion has on electron beam induced deposition are explored via a three-dimensional Monte Carlo simulation. Initially the growth rate and resolution are compared for a common set of deposition conditions with a variable surface diffusion coefficient ranging from 0 to 1 × 10(-8) cm(2) s(-1). The growth rate and resolution are shown to both be enhanced as the growth changes from a mass transport limited regime to a reaction rate limited regime. The complex interplay between the vertical growth rate, the lateral growth rate, the interaction volume and the adsorbed and diffused precursor species are discussed. A second scenario is also simulated in which only gas diffused from a constant source at the perimeter of the simulation boundary is assumed (no gas phase adsorption). At low diffusion coefficients, the diffusing gas is consumed by secondary and backscattered electrons and experimentally observed ring-like structures are generated. At higher diffusion coefficients, the diffusion length is sufficient for the precursor atoms to diffuse to the center (and up the pillar sidewalls) to generate nanowires.
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Affiliation(s)
- Daryl A Smith
- Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA
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Smith DA, Fowlkes JD, Rack PD. Understanding the kinetics and nanoscale morphology of electron-beam-induced deposition via a three-dimensional Monte Carlo simulation: the effects of the precursor molecule and the deposited material. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:1382-9. [PMID: 18720436 DOI: 10.1002/smll.200701133] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The electron-beam-induced deposition of silicon oxide from tetraethyorthosilicate and tungsten from tungsten hexafluoride is simulated via a Monte Carlo simulation. Pseudo one-dimensional nanopillars are grown using comparable electron-beam parameters and a comparison of the vertical and lateral growth rate and the pillar morphology is correlated to the precursor and deposited material parameters. The primary and secondary electrons (type I) are found to dominate the vertical growth rate and the lateral growth rate is dominated by forward and secondary electrons (type II). The resolution and morphology of the nanopillars are affected by the effective electron interaction volume and the resultant surface coverage of the precursor species in the effective electron interaction region. Finally, the simulated results are compared to previously reported experimental results.
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Affiliation(s)
- Daryl A Smith
- Department of Materials Science and Engineering, The University of Tennessee, 434 Dougherty Hall, Knoxville, TN 37996, USA
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Rykaczewski K, Marshall A, White WB, Fedorov AG. Dynamic growth of carbon nanopillars and microrings in electron beam induced dissociation of residual hydrocarbons. Ultramicroscopy 2008; 108:989-92. [DOI: 10.1016/j.ultramic.2008.04.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2007] [Revised: 04/02/2008] [Accepted: 04/15/2008] [Indexed: 11/17/2022]
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Song M, Furuya K. Fabrication and characterization of nanostructures on insulator substrates by electron-beam-induced deposition. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2008; 9:023002. [PMID: 27877950 PMCID: PMC5099707 DOI: 10.1088/1468-6996/9/2/023002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 08/01/2008] [Accepted: 02/19/2008] [Indexed: 05/22/2023]
Abstract
The fabrication, characterization, and decoration with metallic nanoparticles of nanostructures such as nanowhiskers, nanodendrites, and fractal-like nanotrees on insulator substrates by electron-beam-induced deposition (EBID) are reviewed. Nanostructures with different morphologies of whiskers, dendrites, or trees are fabricated on insulator (Al2O3 or SiO2) substrates by EBID in transmission electron microscopes by controlling the irradiation conditions such as the electron beam intensity. The growth of the nanostructure is related to the accumulation of charges on the surface of a substrate during electron-beam irradiation. A high concentration of the target metallic element and nanocrystal grains of the element are contained in the fabricated nanostructures. The process of growth of the nanostructures is explained qualitatively on the basis of mechanisms in which the formation of the nanostructures is considered to be related to the nanoscaled unevenness of the charge distribution on the surface of the substrate, the movement of the charges to the convex surface of the substrate, and the accumulation of charges at the tip of the grown nanostructure. Novel composite structures of Pt nanoparticle/tungsten (W) nanodendrite or Au nanoparticle/W nanodendrite are fabricated by the decoration of W nanodendrites with metallic elements. Because they have superior features, such as a large specific surface area, a freestanding structure on substrates, a typical size of several nanometers of the tip or the branch, and high purity, the nanostructures may have applications in technologies such as catalysts, sensors, and electron emitters. However, there are still some subjects that should be further studied before their application.
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Furuya K. Nanofabrication by advanced electron microscopy using intense and focused beam ∗. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2008; 9:014110. [PMID: 27877936 PMCID: PMC5099805 DOI: 10.1088/1468-6996/9/1/014110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Revised: 05/27/2008] [Accepted: 03/13/2008] [Indexed: 05/19/2023]
Abstract
The nanogrowth and nanofabrication of solid substances using an intense and focused electron beam are reviewed in terms of the application of scanning and transmission electron microscopy (SEM, TEM and STEM) to control the size, position and structure of nanomaterials. The first example discussed is the growth of freestanding nanotrees on insulator substrates by TEM. The growth process of the nanotrees was observed in situ and analyzed by high-resolution TEM (HRTEM) and was mainly controlled by the intensity of the electron beam. The second example is position- and size-controlled nanofabrication by STEM using a focused electron beam. The diameters of the nanostructures grown ranged from 4 to 20 nm depending on the size of the electron beam. Magnetic nanostructures were also obtained using an iron-containing precursor gas, Fe(CO)5. The freestanding iron nanoantennas were examined by electron holography. The magnetic field was observed to leak from the nanostructure body which appeared to act as a 'nanomagnet'. The third example described is the effect of a vacuum on the size and growth process of fabricated nanodots containing W in an ultrahigh-vacuum field-emission TEM (UHV-FE-TEM). The size of the dots can be controlled by changing the dose of electrons and the partial pressure of the precursor. The smallest particle size obtained was about 1.5 nm in diameter, which is the smallest size reported using this method. Finally, the importance of a smaller probe and a higher electron-beam current with atomic resolution is emphasized and an attempt to develop an ultrahigh-vacuum spherical aberration corrected STEM (Cs-corrected STEM) at NIMS is reported.
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Affiliation(s)
- Kazuo Furuya
- High Voltage Electron Microscopy Station, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0003, Japan
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Abstract
A novel nanoscale oxide patterning technique based on electron beam induced transformation in a gas environment is demonstrated. Localized phase transformation is induced in the surface region of a substrate, resulting in the formation of an oxide pattern that is embedded in the surface. The composition of the transformed region is determined only by the substrate and gas composition. The spatial resolution of the technique is about 15 nm.
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Affiliation(s)
- Peter A Crozier
- LeRoy Eyring Center for Solid State Science, School of Materials, Arizona State University, Tempe, Arizona 85287-1704, USA.
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Liu ZQ, Mitsuishi K, Furuya K. Dynamic Monte Carlo simulation on the electron-beam-induced deposition of carbon, silver, and tungsten supertips. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2006; 12:549-52. [PMID: 19830948 DOI: 10.1017/s1431927606060648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The process of electron-beam-induced deposition (EBID) was simulated with a dynamic Monte Carlo profile simulator, and the growth of carbon, silver, and tungsten supertips was investigated to study the dependence of material composition on the spatial resolution of EBID. Because light atoms have a smaller scattering angle and a longer mean free path, the carbon supertip has the smallest lateral size and the highest aspect ratio of a bottom tip compared to silver and tungsten supertips. Thus the best spatial resolution of EBID can be achieved on materials of low atomic number. The calculation also indicated a significant contribution of primary electrons to the growth of a supertip in EBID, which is consistent with the experimental observations. These results lead to a more comprehensive understanding of EBID, which is a complex interaction process between electrons and solids.
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Affiliation(s)
- Zhi-Quan Liu
- High Voltage Electron Microscopy Station, National Institute for Materials Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan.
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White WB, Rykaczewski K, Fedorov AG. What controls deposition rate in electron-beam chemical vapor deposition? PHYSICAL REVIEW LETTERS 2006; 97:086101. [PMID: 17026317 DOI: 10.1103/physrevlett.97.086101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Indexed: 05/12/2023]
Abstract
The key physical processes governing electron-beam-assisted chemical vapor deposition are analyzed via a combination of theoretical modeling and supporting experiments. The scaling laws that define growth of the nanoscale deposits are developed and verified using carefully designed experiments of carbon deposition from methane onto a silicon substrate. The results suggest that the chamber-scale continuous transport of the precursor gas is the rate controlling process in electron-beam chemical vapor deposition.
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Affiliation(s)
- William B White
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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Takeguchi M, Shimojo M, Tanaka M, Che R, Zhang W, Furuya K. Electron holographic study of the effect of contact resistance of connected nanowires on resistivity measurement. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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