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We describe reliable CNT x-ray tubes and their digital properties such as easy modulation of x-ray dose, high-speed operation, and low-voltage and low-power consumption control with an active-current control unit (ACCU) developed. The simple and advanced ACCU was found to shorten the response time of CNT x-ray tube down to sub-microsecond along with stable and reliable operation. The fast digital...
A re-entrant cavity resonator with carbon nanotubes cold cathode was fabricated. The cold cathode was driven by L band signal and a modulated electron emission of CNTs was achieved. An average current of 3.865 µA was recorded when a 1W/1.572GHz signal was led in the cavity, corresponding density of 193.3 µA/cm2. The highest output power was obtained at nearly 1.6S GHz frequency under 100 mW input.
BaO nanostructure was successfully synthesized by a chemical bath deposition method. The morphology, microstructure, and composition of the BaO nanostructure were characterized by field emission scanning electron microscopy. The BaO nanostructure showed good field emission properties, and the emitters constructed of BaO nanostructure exhibited a low turn-on field, a low threshold field, a high field...
A sheet electron beam source is demonstrated using a line-shape carbon nanotube (CNT) field emitter. The line-shape CNT field emitter shows large emission current under the small applied voltage. Moreover, the emitted electron is well-confined without any focusing lens.
We have fabricated pointed graphite emitters (PGEs) from a thin graphite foil by a rather simple cutting technique. After a sudden activation, PGEs reproducibly provide currents up to 3 mA at 4 V/µm, and after 2 h conditioning a nearly stable current of 500 µA over 10 h. Luminescent screen images reveal multiple field emitters from fluctuating spots. Such a PGE was used as reliable electron source...
We herein report field emission characteristics of GdB6 nanostructures grown directly on a pellet via laser processing (laser fluence ∼ 6 J/cm2). The laser processed GdB6 pellet was characterized by X-ray diffraction, which revealed no change in phase upon laser processing. The values of the turn-on field required to draw emission current density of 1 µA/cm2 is found to be ∼ 2.95 V/µm, for the laser...
We use chemical oxidation to make the gram scale graphene oxide and exfoliate the graphene from carbon fiber clothe. Then the graphene oxide is made as low operating electric field emitter by electrophoretic. Notably, the exfoliated graphene on carbon cloth has excellent field emission properties, with turn-on field at 0.4V/µm and threshold-field at 0.7V/µm. And aligned graphene sheets are horizontal...
The ultra-high vacuum measurement properties are investigated on the Leybold extract gauge based on carbon nanotube (CNT) field emission. The CNT field emitters are grown directly on catalytic substrates with strong nanotube adhesion, excellent emission properties, and low outgassing effect. The CNT gauge responds linearly to nitrogen pressure in the range from 10−6 to 10−11 Torr with sensitivities...
Polycrystalline CVD diamond films were thermally oxidized in order to obtain single-crystal diamond needles. Field electron emission properties of the needles were studied using UHV system equipped with an electron energy analyzer. Current-voltage characteristics have shown strong current saturation that is predicted by the basic theory of the electron emission from semiconductors. Using the energy...
An in-place synthesis process for nanowires is used to fabricate a customized field emitter array for the use as a non-thermal electron source in an ionization gauge. The fabrication was further expanded to metallic nanocones with a density of 1.6 × 106 cm−2 using optimized deposition of the cones on predefined electrodes. This method can make the wide area of the predefined electrodes enclosed with...
We report on gated p-type Si-tip array cathodes for implementation into field emission electron sources for sensor applications. Arrays of 16 and 100 tips with tip heights of 3 µm and tip radii below 30 nm with integrated gate electrodes concentrically positioned 2 µm below the tip apexes were fabricated using an improved process, which leads to an enhanced isolation layer quality with sufficient...
Synthesis of SnS/TiO2 nanocomposite was done by thermal evaporation method. The field emission characteristics have been investigated at room temperature. The field emission current density versus applied field (J-E) and emission current versus time (I-t) characteristics were measured in a planer diode configuration at the base pressure of 1 × 10−8 mbar. Turn-on field defined for the emission current...
Graphene and its derivatives are expected to be efficient field emitters due to their unique geometry and electrical properties. In this work we have decorated Graphene nanosheets with noble metal nanoparticles specifically Platinum by simple chemical route which produces high density of protrusions. The assynthesized Graphene nanosheets were characterized using XRD and TEM. The values of turn-on...
Aligned square arrays of black silicon (b-Si) on top of pillars were fabricated on p-type silicon substrate by a deep-etching step combined with a b-Si process. Two 10×10 arrays with pillar heights of 8 µm and 20 µm and one b-Si reference sample without pillars were investigated. Integral field emission (FE) measurements of the arrays yielded rather low onset-fields between 6.4 V/µm and 13.5 V/µm...
We received and compared the current-voltage characteristics (IVC) of the multi-tip field nanocomposite emitters in the slow and the fast high voltage scanning modes. We found two types of hysteresis on the emission characteristics plots in the same field experiment. The study of IVC form depending on the duration and amplitude of the scanning voltage was carried out.
We have optimized the aging process of fully vacuum-sealed carbon nanotube (CNT) X-ray tubes in terms of an anode voltage, a cathode current and pulse on-time. Degradation and electrical arcing have been monitored and severely suppressed during the aging process. The completely aged CNT X-ray tube with an outer diameter of 15 mm and a length of 60 mm shows a cathode current of 3 mA at an anode voltage...
The paper describes a MEMS-type field emission electron source fabricated as a planar silicon structure bonded to a glass substrate. The source consists of a carbon nanotube cathode, beam formation electrodes and vacuum housing; all made in uniform technological process. Complete fabrication process of the test structures has been successfully elaborated and implemented. Emission properties obtained...
Patterned tungsten oxide (WO3) nanowires are grown on ITO glass substrate by a thermal oxidation without any catalyst. Field emission measurements show that the field emission current of WO3 nanowires can be dramatically enhanced by a conditioning process. After conditioning, the turn-on voltage of the WO3 nanowires decreases from 6.50 MV/m to 3.28 MV/m. The phenomenon is related the oxygen adsorbate...
Field emission features and FIM/FEM images from vacuum arc-prepared carbon films on shape-controlled W tip apexes have been examined, where tens of samples with different film thicknesses and different radii were prepared. The obtained results imply that superior field emission is not due to the protrusions with high aspect ratio but its intrinsic nano-structures.
We report for the first time field electron emission investigations on few layered black phosphorous nanosheets emitter's synthesized using chemical method with thickness ∼ 2–5 nm. The turn-on electric field required to draw an emission current density of ∼10 µA/cm2 was found to be ∼ 4.2 V/µm. Furthermore, a few layer black phosphorous nanosheets emitter deliver an large emission current density of...
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