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Transparent gate-structured field emitter arrays (FEAs) using ZnO nanowire cold cathode were fabricated. By using indium tin oxide(ITO) as the materials for both the cathode and gate electrode, the ZnO nanowire FEAs shows more than 76% transmission in the visible light region. Such transparent FEAs have potential applications in double-sided field emission display.
The scaling down of thermionic emitters to the microscale is achieved by using microfabrication technologies and graphene working as the emitter. A graphene micro-emitters can be turned on by a voltage of several volts and its emission current exhibits a tunability of up to six orders by a modest gate. Importantly, emission performances of graphene micro-emitters are controllable and repeatable through...
Radiation tolerance of a field emitter array and a cadmium telluride-based photoconductor was investigated. The variation of the performance of these devices were investigated during the γ-ray irradiation by every 100–200 kGy. Total dose of irradiation reached 1.2 MGy, but no significant deterioration of the properties has been observed. A test tube exhibited successful photo-signal detection even...
The influence of Na and Cl atoms adsorption on the work functions (WF) of graphene was investigated by first-principles calculations. The WF of graphene increase or decrease significantly by a single Na or Cl atom adsorption. When Na and Cl adatoms were co-adsorbed on opposite sides of grapheme, there is a little change in WF of grapheme, but there is great difference of the WF between the two sides.
Here we propose a model to simulate the influence of atomistic properties of field emitters on the field emission current. As an example, we modeled the field emission from a zigzag-single walled carbon nanotube. By a modification in the self-energy in non-equilibrium Green's function formalism, we simulated the field emission current, considering quantum transport of electrons within the carbon nanotube...
X-ray tubes with an electron source of carbon nanotubes (CNTs) have often been fabricated by vacuum brazing at high temperature, during which CNT emitters have been frequently damaged probably by reacting with other ingredients incorporated into the CNT paste. In particular, some metal or oxide fillers seemed to accelerate the catalytic decomposition of CNTs during high-temperature treatment. In this...
The B/LaB6 hierarchical heterojunction nanostructures have been successfully fabricated on Si substrate by CVD technique. The branch-like morphology may be beneficial to improving their field emission (FE) properties by increasing the aspect ratio or growth density of the emitters. The results show that the threshold field of the B/LaB6 branch-like nanoheterojunctions is 21.6 V/μm (@1 mA/cm2) and...
By depositing thin layers of ∼17nm and ∼60nm of Ba on nanocrystalline graphite/CNT emitters, it was expected that the current density of the emitters, at a given extraction field, would increase by several orders of magnitudes due to the lowering of the emitter work function. The opposite of what was expected occurred. A drastic decrease in emission current was observed. Since field emission is also...
We propose a fabrication method of gold nano-pillar structures with the aspect ratio up to ∼38. The optical electric field enhancement of density and height controlled gold nano-pillar arrays were experimentally studied by ultrafast near infrared photoemission. Strongly polarization dependent multi-photon photoemission was observed and compared with numerical simulation. The results show that such...
Amorphous indium-gallium-zinc-oxide thin film transistor (a-IGZO TFT) with offset structure is fabricated for active-driving of ZnO nanowire field emitters. ZnO nanowire field emitters grown by thermal oxidation method is integrated with the a-IGZO TFT. The results proved that the growth process of ZnO nanowires is compatible with the a-IGZO TFT fabrication process.
The effect of gate mesh electrode on the electron extraction from carbon nanotube emitters for high performance electron beam were studied. In the case of low electron emission regime (< 1mA/cm2), gate electrode structure and materials little effects on electron emission current. However, higher electron emission regime (>1mA/cm2) gate electrode materials and structure start to effects on electron...
This study investigated the effect of boron and phosphorus compounds on the thermal stability and oxidation resistance of carbon nanotubes (CNTs). Addition of these compounds evidently increased oxidation temperatures of CNTs probably by poisoning chemically their active sites. We applied the CNTs treated with boron and phosphorus compounds to the CNT paste emitters for electron sources of x-ray tubes...
The monomer pyrrole has been polymerized by chemical route in the presence of graphene oxide (GO), reduced graphene oxide (rGO) and graphene nanoribbons (GNR) separately to prepare nanocomposites as Polypyrrole-GO (PGO), PPy-rGO (PRGO), PPy-GNR (PGNR), respectively. The morphological, chemical and structural characterization of the as-synthesized products was carried out using scanning electron microscopy...
We have implemented experimental methods for determining emission area parameters by using online processing of current-voltage characteristics (IVC). We calculated the formal emission area for each experimental IVC: for a single tungsten emitter and for several multi-tip emitters based on CNT and graphene. Voltage dependence in emission area is observed.
What we report here, is the effect of visible light irradiation on field emission(EF) current from three different cathods: vertically aligned CNTs, bundled vertical CNTs, and Ag-nanoparticle deposited CNTs. A full discussion on the responsible phenomena for different responses of samples is presented in this work.
In this report, we present a modification in non-equilibrium Green's function method to investigate structural effects of the emitter on field emission current. Effect of applied uniaxial strain can also be studied using our modified formalism. Moreover a practical method to consider the effect of device parameters such as channel length, anode-cathode separation and gate potential can be provided...
We developed a field emission nano-focus x-ray source using carbon nanotube (CNT) emitters and electron beam (E-beam) focusing modules, which could be used in the applications requiring the high-resolution x-ray images. For the nano-size focusing of E-beam from CNT emitters, we designed special focusing modules consisting of electrostatic and magnetic lenses. The geometries and operating conditions...
We investigated the hysteresis phenomenon in current-voltage characteristics of multipoint emitters based on nanocomposites with carbon nanotubes and graphene. The conditions under which the change in shape of the hysteresis from “direct” to “reverse” or vice versa occurs were found. Mass-spectrometer data allowed to associate hysteresis with adsorbed particles a source of which is the anode.
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