An ultrabright and monochromatic electron point source made of a LaB6 nanowire

Zhang, Han; Tang, Jie; Yuan, Jinshi; Yamauchi, Yasushi; Suzuki, Taku; Shinya, Norio; Nakajima, Kiyomi; Qin, Lu Chang

doi:10.1038/nnano.2015.276

Cited by 127 publications

(79 citation statements)

References 35 publications

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“…The emission current density is calculated to be 2.31 mA cm −2 at V driven = 3.05 V. An impressive low emission current fluctuation is observed, the relative standard deviation (RSD) of I collect over 30 min is as small as ±1.2%. Figure b shows the vacuum level and fluctuation of our micro‐emitters, compared with previously reported FEAs . As we can clearly see, emission current fluctuation of FEAs decreases with vacuum level improvement due to suppressed residual gas adsorption and ion back bombardment.…”

Section: Resultsmentioning

confidence: 76%

High‐Performance On‐Chip Thermionic Electron Micro‐Emitter Arrays Based on Super‐Aligned Carbon Nanotube Films

Wang

Yang

et al. 2019

Adv Funct Materials

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An important advancement towards the realization of miniaturized and fully integrated vacuum electronic devices will be the development of on‐chip integrated electron sources with stable and reproducible performances. Here, the fabrication of high‐performance on‐chip thermionic electron micro‐emitter arrays is demonstrated by exploiting suspended super‐aligned carbon nanotube films as thermionic filaments. For single micro‐emitter, an electron emission current up to ≈20 µA and density as high as ≈1.33 A cm−2 are obtained at a low‐driven voltage of 3.9 V. The turn‐on/off time of a single micro‐emitter is measured to be less than 1 µs. Particularly, stable (±1.2% emission current fluctuation for 30 min) and reproducible (±0.2% driven voltage variation over 27 cycles) electron emission have been experimentally observed under a low vacuum of ≈5 × 10−4 Pa. Even under a rough vacuum of ≈10−1 Pa, an impressive reproducibility (±2% driven voltage variation over 20 cycles) is obtained. Moreover, emission performances of micro‐emitter arrays are found to exhibit good uniformity. The outstanding stability, reproducibility, and uniformity of the thermionic electron micro‐emitter arrays imply their promising applications as on‐chip integrated electron sources.

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Section: Resultsmentioning

confidence: 76%

High‐Performance On‐Chip Thermionic Electron Micro‐Emitter Arrays Based on Super‐Aligned Carbon Nanotube Films

Wang

Yang

et al. 2019

Adv Funct Materials

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“…Its ability to emit electrons has been widely exploited in last 60 years since the pioneering work of Lafferty on sintered hexaboride ceramics 6 . It has been used to build hot cathodes for a large variety of applications, including electron guns in cathode tubes 7 , cathodes for plasma production 8, 9 and electron microscopes 10, 11 . While at present, mainly single crystalline emitters are used, sintered ceramics show thermionic properties as well, and historically they have been the first to be studied 6, 7, 12 .…”

Section: Introductionmentioning

confidence: 99%

Lanthanum hexaboride for solar energy applications

Sani

Mercatelli

Meucci

et al. 2017

Sci Rep

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We investigate the optical properties of LaB6 – based materials, as possible candidates for solid absorbers in Concentrating Solar Power (CSP) systems. Bulk LaB6 materials were thermally consolidated by hot pressing starting from commercial powders. To assess the solar absorbance and spectral selectivity properties, room-temperature hemispherical reflectance spectra were measured from the ultraviolet to the mid-infrared, considering different compositions, porosities and surface roughnesses. Thermal emittance at around 1100 K has been measured. Experimental results showed that LaB6 can have a solar absorbance comparable to that of the most advanced solar absorber material in actual plants such as Silicon Carbide, with a higher spectral selectivity. Moreover, LaB6 has also the appealing characteristics to be a thermionic material, so that it could act at the same time both as direct high-temperature solar absorber and as electron source, significantly reducing system complexity in future concentrating solar thermionic systems and bringing a real innovation in this field.

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“…Silicon oxide in the nanogap spaced by 18 nm wide CNT electrodes exhibited similar RS and EE characteristics to those presented in Figure 1c after electroforming, and an emission current of up to 2.8 µA was measured ( Figure S7, Supporting Information). [7] To quantitatively describe the EE from the EEND, a model based on the above picture of the M-I-M tunneling diode was proposed to calculate the emission current of the EEND from its conduction current. Electrons are therefore emitted at a distance comparable to the mean free path for impact ionization after entering the opposite metallic region.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

Silicon Oxide Electron‐Emitting Nanodiodes

Tang

et al. 2018

Adv Elect Materials

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Electrically driven on‐chip electron sources that do not need to be heated are long pursued, but their realization remains challenging. Here, it is shown that a nanogap formed by two electrodes on a silicon oxide substrate functions as an electron‐emitting nanodiode after the silicon oxide in the nanogap is electrically switched to a high‐resistance conducting state. A nanodiode based on graphene electrodes can be turned on by a voltage of ≈7 V in ≈100 ns and show an emission current of up to several microamperes, corresponding to an emission density of ≈106 A cm−2 and emission efficiency as high as 16.6%. We attribute the electron emission to be generated from a metal–insulator–metal tunneling diode on the substrate surface formed by the rupture of conducting filaments in silicon oxide. An array of 100 nanodiodes exhibits a global emission density of 5 A cm−2 and stable emission with negligible current degradation over tens of hours under modest vacuum. The combined advantages of a low operating voltage, fast temporal response, high emission density and efficiency, convenient fabrication and integration, and stable emission in modest vacuum make silicon oxide electron‐emitting nanodiodes a promising on‐chip electron sources.

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An ultrabright and monochromatic electron point source made of a LaB6 nanowire

Cited by 127 publications

References 35 publications

High‐Performance On‐Chip Thermionic Electron Micro‐Emitter Arrays Based on Super‐Aligned Carbon Nanotube Films

High‐Performance On‐Chip Thermionic Electron Micro‐Emitter Arrays Based on Super‐Aligned Carbon Nanotube Films

Lanthanum hexaboride for solar energy applications

Silicon Oxide Electron‐Emitting Nanodiodes

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