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Vacuum micro/nano electronic devices possess merits of radiation hardness, temperature tolerance, high working frequency and output power. It's regarded as the promising candidates for the application on ultra-high speed transistor [1, 2], portable and fast-switch X-ray source [3], free electron laser [4], field emission display [5] and so on. In the developing of modern vacuum electronic, to achieve...
New device concepts and materials for the fabrication of compact THz (> 100 GHz) nanoelectronic and vacuum nanoelectronic devices are of particular interest for broadband communication, security screening of packages and chemical materials, biomedical examination, and other applications. In particular, new compact and room-temperature THz imaging systems as well as environmental monitoring are...
In this work, we analyze properties of cold field emission from a low-dimensional, paraboloidal emitter tip. We find that the entirety of the emitted current density (ECD) originates from a few high-energy, zero-angular-momentum subbands and from a region on the tip that is highly localized around the apex. In addition, Fowler-Nordheim (FN) plots for such emitters are non-linear and do not serve as...
ZnO nanowire field emitter arrays with non-coplanar focus electrode structure was designed. A simulation was conducted to verified the focusing ability of the focus electrode structure. The designed structure was realized successfully and the growth condition of ZnO nanowires in the structure was studied.
Nitrogen-incorporated ultrananocrystalline diamond, (N)UNCD, is an unconventional field emitter that performs in planar thin film configuration and has turn-on fields on the order of 10 V/ m. To shed more light on fundamental field emission properties of (N)UNCD, we have designed and commissioned a field emission microscope (FEM). The microscope can directly image the field emission site distribution...
Nanostructured thermionic energy converters may offer substantial advantages over traditional devices by reducing system complexity and requirements. However, they still face similar fundamental challenges, such as anode collection efficiency and the space charge effect, which have limited their performance to date. Here, we investigate a carbon nanotube-based thermionic converter, demonstrating that...
The cold cathode x-ray source was fabricated by using the point-type CNT film emitter. The CNT x-ray source consists of the CNT point emitter, the metal mesh gate electrode and the tungsten target anode electrode. Those components were mounted in a small vacuum chamber. The fabricated CNT x-ray source shows a high resolution x-ray image at a low anode current and at a low anode voltage compared to...
We fabricated field emission electron sources and applied for the glass sealed x-ray tube for medical imaging devices. The x-ray tube consists of an electron beam with a patterned grown CNT emitters with RAP process. Those electron beam shows higher electron emission current and transmittance after glass seal. With the x-ray tube, we success to measure medical image with finger and high resolution...
Ion mobility spectrometers (IMS) are measurement devices for fast and ultra-sensitive trace gas analysis. Most IMS employ radioactive electron sources, such as 3H or 63Ni, to provide free electrons with high kinetic energy at atmospheric pressure for initiating a chemical gas phase ionization of the analytes. The disadvantage of these radioactive materials are legal restrictions and the electron emission...
A new way to improve the current stability of an in-plane gated CNT emitters cathode with a closed loop control has been investigated. Ageing has been performed with a variation of external conditions by introducing hydrogen into the vacuum chamber and resulting in a low impact on the stability due to the feedbacked adjustment of the local electric field at the apex of CNTs given by the closed loop...
The feasibility of preparation of nanowire on glass favors the realization of large area devices, which makes nanowire field emitter arrays (FEAs) good candidate for large-area vacuum microelectronics applications. In this study, a coaxial gated ZnO nanowire FEAs was fabricated. Effective emission current modulation by the gate voltage was achieved and the addressing capability was demonstrated.
An in-situ fabrication technique based on ion track etched template electrodeposition of metallic nanocones was used for the production of field emitter cathodes. Gold nanocones with a height of 24 microns, a base diameter between 3 to 4 microns and a tip diameter below 300 nanometers were deposited on a circular electrode with a diameter of 2.5 mm. The integral field emission (FE) measurements of...
We fabricated a high performance electron beam for the vacuum electronic devices with carbon nanotube (CNT) cathode. For the vacuum electronic devices application, a structure of cold cathode should be highly adhere on cathode substrate and endure a resistive heating during electron emission. For fabrication of stable electron beam, we optimized the CNT emitters and the triode structure. The structural...
We report on field-emission investigations of micro-structured stainless steel. The most important result is that the threshold field strength is not even four times greater than an equivalent-sized CNT field-emitter array. Stainless steel can used as large-area field-emission cathode in vacuum components.
The three-dimensional epitaxial technique allows the realization of gallium nitride lines in addition to the rods. To optimize the properties of GaN-based field emission cathodes further investigations and an improvement of the epitaxial process were performed. The microrods and microlines consist of a one-order higher n-doped gallium nitride in comparison to the gallium nitride layer on the sapphire...
Microstructured silicon carbide field emission arrays has been combined with field electrode or gate acting on arrays of nanotips. Simulation results demonstrate rather high emission current density at relatively low operating voltage on the gate.
Silicon carbide field emission arrays coated with two different type of nanocrystalline diamond thin film: undoped and highly boron-doped are compared. The last one shows two times lower electric field threshold for electron emission.
High brightness and stable cathode has been required for SEM use. We have been studied about Tungsten Carbide (WC) field emission cathode to achieve low-cost and easy to use, high brightness cathode. Tungsten carbide layer is formed on W-FE tip by heating in Ethylene(C2H4) gas. This WC field emission cathode indicated low work function.
Field emission of high current from carbon nanotube (CNT) emitters usually enforces them to be exposed to high electric fields (electrostatic forces) and Joule heating. In addition, vacuum packaging of field emitter devices are often carried out at high temperature. Under such circumstances, CNT emitters may be easily damaged, thus requiring highly crystalline and thermally stable CNTs. This study...
We tried to improve field emission properties of carbon nanotube (CNT) paste emitters by controlling the size distribution of aggregated SiC fillers. The SiC fillers used as an adhesion promoter strongly affects the dispersion of CNT paste, determining uniformity and reproducibility of the field emitter. We found, to date, that the optimum distribution is about 1 μm of D50, the value of the particle...
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