Evaluating Angular Ion Current Density for Atomically Defined Nanotips

Urban, R.; Wolkow, Robert A.; Pitters, Jason

doi:10.1017/s1431927614001627

Cited by 7 publications

(5 citation statements)

References 26 publications

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“…The electron beam spot size of the 14 × 14 CNT emitters can be analyzed with the help of the FEM image. The symmetrically distributed electron beam spot is well described by the Gaussian distribution 7 , 50 , , Where , and represents the peak intensity, mean (maximum peak intensity), and standard deviation of the distribution respectively. In the electron beam spot profile, the width of the intermediate of the maximum intensity value represents the FWHM which is expressed as .…”

Section: Resultsmentioning

confidence: 99%

Optimization of vertically aligned carbon nanotube beam trajectory with the help of focusing electrode in the microchannel plate

Adhikari,

Ketan,

Patil

et al. 2023

Sci Rep

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The focusing electrode plays an important role to reduce the electron beam trajectory with low dispersion and high brightness. This article summarizes the importance of the vertically aligned multi-walled carbon nanotube effect with the focusing electrode. First of all, the effect of electron beam trajectory is studied with the different heights, hole sizes, and applied voltage of the focusing electrode by the opera 3D simulation. The field emission electron beam spot is captured in the microchannel plate which helps to reduce the signal noise effect and damage of CNT tips by the joule heating effect. The high-dense bright spot is optimized at the focusing electrode hole size of 2 mm, and the height of 1 mm from the gate mesh electrode at the low bias voltage of − 200 V without the loss of current. The FWHM of the electron beam is calculated 0.9 mm with its opening angle of 0.9° which could be applicable in high-resolution multi-electron beam microscopy and nano-focused X-ray system technology.

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Section: Resultsmentioning

confidence: 99%

Optimization of vertically aligned carbon nanotube beam trajectory with the help of focusing electrode in the microchannel plate

Adhikari,

Ketan,

Patil

et al. 2023

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The pattern of the high-dense bright spot has a circular spot, and the intensity profile of the beam spot can be well described by a Gaussian distribution,

, where

, and

represent the peak intensity, the maximum point of peak intensity and the standard deviation, respectively. The fullwidth half maximum of the electron beam can be expressed as FWHM =

, where σ is the standard deviation [ 21 , 51 ]. Figure 6 explains the analysis of the intensity profile of the high-dense electron beam spot of Figure 4 .…”

Section: Resultsmentioning

confidence: 99%

Beam Trajectory Analysis of Vertically Aligned Carbon Nanotube Emitters with a Microchannel Plate

et al. 2022

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Vertically aligned carbon nanotubes (CNTs) are essential to studying high current density, low dispersion, and high brightness. Vertically aligned 14 × 14 CNT emitters are fabricated as an island by sputter coating, photolithography, and the plasma-enhanced chemical vapor deposition process. Scanning electron microscopy is used to analyze the morphology structures with an average height of 40 µm. The field emission microscopy image is captured on the microchannel plate (MCP). The role of the microchannel plate is to determine how the high-density electron beam spot is measured under the variation of voltage and exposure time. The MCP enhances the field emission current near the threshold voltage and protects the CNT from irreversible damage during the vacuum arc. The high-density electron beam spot is measured with an FWHM of 2.71 mm under the variation of the applied voltage and the exposure time, respectively, which corresponds to the real beam spot. This configuration produces the beam trajectory with low dispersion under the proper field emission, which could be applicable to high-resolution multi-beam electron microscopy and high-resolution X-ray imaging technology.

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“…The electron beam pattern was observed by optical microscope and was measured with an image analysis tool to obtain the correct beam size. Beam size values of 55 μm and 114 μm were obtained from the full width at half maximum (FWHM) value at the bright spot using Gaussian four-peak parameter fitting [ 33 ]. As a result of emission patterns, the solid angles of 1560- and 550-CNT emitters were 0.053 and 0.2 sr, respectively, at an emission current of 1 μA.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the Effect of Structural Properties of a Vertically Standing CNT Cold Cathode on Electron Beam Brightness and Resolution of Secondary Electron Images

et al. 2021

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Carbon nanotube (CNT)-based cold cathodes are promising sources of field emission electrons for advanced electron devices, particularly for ultra-high-resolution imaging systems, due to their high brightness and low energy spread. While the electron field emission properties of single-tip CNT cathodes have been intensively studied in the last few decades, a systematic study of the influencing factors on the electron beam properties of CNT cold cathodes and the resolution of the secondary electron images has been overlooked in this field. Here, we have systematically investigated the effect of the structural properties of a CNT cold cathode on the electron beam properties and resolution of secondary electron microscope (SEM) images. The aspect ratio (geometric factor) and the diameter of the tip of a vertically standing CNT cold cathode significantly affect the electron beam properties, including the beam size and brightness, and consequently determine the resolution of the secondary electron images obtained by SEM systems equipped with a CNT cold cathode module. Theoretical simulation elucidated the dependence of the structural features of CNT cold cathodes and electron beam properties on the contribution of edge-emitted electrons to the total field emission current. Investigating the correlations between the structural properties of CNT cold cathodes, the properties of the emitted electron beams, and the resolution of the secondary electron images captured by SEM equipped with CNT cold cathode modules is highly important and informative as a basic model.

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Evaluating Angular Ion Current Density for Atomically Defined Nanotips

Cited by 7 publications

References 26 publications

Optimization of vertically aligned carbon nanotube beam trajectory with the help of focusing electrode in the microchannel plate

Optimization of vertically aligned carbon nanotube beam trajectory with the help of focusing electrode in the microchannel plate

Beam Trajectory Analysis of Vertically Aligned Carbon Nanotube Emitters with a Microchannel Plate

Investigation of the Effect of Structural Properties of a Vertically Standing CNT Cold Cathode on Electron Beam Brightness and Resolution of Secondary Electron Images

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