Characterization of ultrasharp field emitters by projection microscopy

Fransen, M.; Damen, E. P. N.; Schiller, Christoph; Rooy, T.L. van; Groen, H.B; Kruit, P.

doi:10.1016/0169-4332(95)00358-4

Cited by 11 publications

(6 citation statements)

References 5 publications

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“…Nanometric tungsten tips are shown to be coherent point sources of electrons, providing exceptionally bright electron beams in dc field emission [41,42]. The appropriate electron optics comprising a focusing Einzel lens together with a quadrupole deflector and a deceleration stage is currently tested.…”

Section: Discussionmentioning

confidence: 99%

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

et al. 2014

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Surface-electrode chips are a versatile and well-established tool for trapping and guiding charged particles. The technique, usually applied to ions, has recently been adapted for electrons using a twodimensional quadrupole guide at microwave driving frequencies. During injection into the guiding potential, the electron trajectories show a strong dependence on the phase and amplitude of fringing electric fields at the coupling entrance of the guide. Here we study the corresponding electron dynamics using a pulsed electron source with pulse durations of several 100 ps to temporally resolve fringing electric fields oscillating at the microwave drive frequency. By synchronizing the timing of the electron pulses to a certain microwave phase, we can increase the electron guiding efficiency by 50%. Furthermore, we present numerically optimized electrode structures for which the amplitude of fringing electric fields at the coupling entrance of the guide is drastically reduced. Particle-tracing simulations suggest that the optimized electrode layout allows the direct injection of electrons into the lowest-lying motional quantum states of the transverse guiding potential.

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Section: Discussionmentioning

confidence: 99%

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

et al. 2014

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“…In spite of the use of poly-crystal W tips, those values were close to the effective source sizes of the nanotips or nanotubes as estimated using Fresnel edge fringes. 8,9 In the meantime, if the Fresnel edge fringe method was valid and the source size was constant, ξ Tb on the screen and, consequently, the effective source size would remain constant regardless of the magnification ratio.…”

Section: Resultsmentioning

confidence: 99%

“…6 Actually, the transverse coherence length (TCL) of E-Beams from various field emitters has been measured using Fresnel edge fringe patterns at the edge of carbon films in FPM images. [7][8][9] However, the visibility of Fresnel edge fringes depends on the straightness of the edge and its thickness, 10 which cannot be determined in the FPM. By employing highly coherent FE sources in our lowtemperature FPM, we have been able to take some of the best quality interference or diffraction images.…”

Section: Introductionmentioning

confidence: 99%

Electron Beam Coherency Determined from Interferograms of Carbon Nanotubes

Cho¹,

Oshima²

2013

Bulletin of the Korean Chemical Society

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A field emission projection microscope was constructed to investigate the atomic and chemical-bonding structure of molecules using electron in-line holography. Fringes of carbon nanotube images were found to be interferograms equivalent to those created by the electron biprism in conventional electron microscopy. By exploiting carbon nanotubes as the filament of the electron biprism, we measured the transverse coherence length of the electron beam from tungsten field emitters. The measurements revealed that a partially coherent electron-beam was emitted from a finite area.

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“…A different method to measure dv is to use a demagnifying lens to focus the electron beam from the gun unit into a spot which is source-size dominated (relatively low contributions from lens aberrations), and then measure the spot size of the beam by scanning it across a knife edge [38,39]. Another method is to place a knife edge at a small distance (less than a few micrometers) from an emitter and to measure the angular width of the Fresnel fringes patterns [13,40]. In this technique, the intensity distribution shape of the source is assumed to be a Gaussian function, and the values of magnification and electron wavelength are needed to extract dv.…”

Section: Source Electron Optics Parametersmentioning

confidence: 99%

A Review Paper on “Graphene Field Emission for Electron Microscopy”

Shao¹,

Khursheed²

2018

Preprint

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Although good field emission from graphene has been demonstrated from a wide variety of different microfabricated structures, very few of them can be used to improve the design of cold field emitters for electron microscopy applications. Most of them consist of densely packed nano-emitters, which produce a large array of defocused overlapping electron beams, and therefore cannot be subsequently focused down to a single nanometer electron probe. This paper reviews the kind of single-tip cathode structures suitable in cold field emission guns for instruments such as scanning electron microscopy, transmission electron microscope or scanning transmission electron microscopy, and reviews progress in fabricating them from graphene-based materials.

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Characterization of ultrasharp field emitters by projection microscopy

Cited by 11 publications

References 5 publications

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

Electron Beam Coherency Determined from Interferograms of Carbon Nanotubes

A Review Paper on “Graphene Field Emission for Electron Microscopy”

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Characterization of ultrasharp field emitters by projection microscopy

Cited by 11 publications

References 5 publications

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

Phase-Resolved Electron Guiding in Optimized Chip-Based Microwave Potentials

Electron Beam Coherency Determined from Interferograms of Carbon Nanotubes

A Review Paper on &ldquo;Graphene Field Emission for Electron Microscopy&rdquo;

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A Review Paper on “Graphene Field Emission for Electron Microscopy”