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Time-and-Space Resolved Cathode Plasma Expansion Velocities in Magnetically Insulated Coaxial Diode With a Metal-Dielectric Cathode
摘要： Time-and-space resolved cathode plasma expansion velocities in magnetically insulated coaxial diodes (MICD) with edged cathodes made of bronze dielectric, bronze, and graphite have been compared through optical diagnosis. The voltage and current of the diode pulse of 260 ns are about 400 kV and 2.8 kA, respectively. The axial and radial expansion velocities of the cathode plasma were obtained through the angled lateral view by utilizing high-speed framing camera combined with the digital image processing methods. In addition, the evolution of the cathode and collector plasmas was visible firstly on the front view at the same time. The bronze-dielectric cathode not only showed low expansion velocity of about 0.5 cm/μs but also had other superior characteristics indicated by the strong emission capability, the fast plasma formation and the uniform plasma distribution. Thereby, the metal–dielectric cathode is a good candidate for applications in a long-pulsed MICD.
关键词： Bronze-dielectric cathode,plasma expansion velocities,high-speed framing camera (HSFC),magnetically insulated coaxial diode (MICD)
更新于2025-09-23 15:23:52
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Simultaneous Cr(VI) removal and bisphenol A degradation in a solar-driven photocatalytic fuel cell with dopamine modified carbon felt cathode
摘要： In this work, a carbon felt cathode modified by dopamine (DPA/CF) was explored to enhance the cathodic reduction of Cr(VI) in a two chambers photoelectrochemical system, which was driven by solar light irradiation using BiVO4 photoanode. In the anode chamber, the bisphenol A (BPA) decomposition can be significantly improved by increasing pH to 8. The electron-hole pairs photogenerated on the surface of BiVO4 were efficiently separated by the application of the DPA/CF cathode. At the optimal conditions, 86% of low-concentration BPA was removed within 60 min. In the cathodic chamber, 80% of Cr(VI) was removed at pH of 4. Based on the XPS and electrochemical analyses, it was proposed that the positively-charged groups on the DPA/CF cathode led to the multilayer adsorption of Cr(VI) anions, which enhanced the reduction of Cr(VI) with the electrons generated on the BiVO4. On the other hand, the CeO groups on the DPA/CF electrode also played an important role as electron transfer mediator for Cr(VI) reduction. The prepared DPA/CF cathode associated with BiVO4 photoanode could be a potential application for efficient removal of Cr(VI) and organic pollutants under solar light irritation.
关键词： BiVO4 photoanode,Carbon felt cathode,Dopamine,Cr(VI),Solar photocatalysis,BPA
更新于2025-09-23 15:23:52
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Doping induced performance enhancement in inverted small molecule organic photodiodes operating below 1V reverse bias - Towards compatibility with CMOS for imaging applications
摘要： Organic photodiodes (OPDs) offer a myriad of advantages over conventional inorganic photodetectors, making them particularly attractive for imaging application. One of the key challenges preventing their utilization is the need for their integration into the standard CMOS processing. Herein, we report a CMOS-compatible top-illuminated inverted small molecule bi-layer OPD with extremely low dark leakage current. The device utilizes a titanium nitride (TiN) bottom electrode modified by a [6,6]-phenyl C61 butyric acid methyl ester (PCBM) cathode buffer layer (CBL). We systemetically show that doping the CBL enhances device's low voltage (below 1 V reverse bias) photoresponse by increasing the linear dynamic range (LDR) and making the bandwidth of the photodidoe broader without compromising the leakage current. The optimized device exhibits a dark leakage current of only ~ 6 x 10-10 A/cm2 at -0.5 V. The external quantum efficiency (EQE) at 500 nm reaches 23% with a calculated specific detectivity as high as 7.15 x 1012 cm Hz1/2/W (Jones). Also the LDR approaches 140dB and the bandwidth is about 400kHz, at -0.5 V bias. The proposed device structure is fully compatible with CMOS processing and can be integrated onto a CMOS readout circuit offering the potential to be applied in high-performance large-scale imaging arrays.
关键词： Interface engineering,Doping,CMOS,Titanium nitride,Organic photodiode,Cathode buffer layer
更新于2025-09-23 15:23:52
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Cathodoluminescent lamp for general lighting using carbon fiber field emission cathode
摘要： The prototype of cathodoluminescent bulb for general lighting with field emission cathode on the basis of carbon fiber is manufactured. The bulb comprises a high-voltage built-in AC-DC converter of the electric line voltage and a standard E27 cap. A high frequency converter is used to obtain high voltage. The anode voltage relative to the modulator is up to +20 kV; the cathode voltage is up to –4 kV; the current value is of the order of 1 mA. The voltage converter is located in the bulb cap and around the neck of the glass envelope.
关键词： cathode-ray-tube phosphor,carbon fiber,light sources,field emission cathodes,cathodoluminescence
更新于2025-09-23 15:22:29
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Polymer light-emitting displays with printed cathodes
摘要： High-resolution passive-matrix polymer light-emitting displays with printed cathodes are achieved by combining delicate cathode deposition and multifunctional buffer layer fabrication. Unlike other printing methods and printed materials, ink-jetting conducting nano-particles as cathode can provide high-resolution cathode patterns and excellent continuity along the fine cathode lines without any mechanical pressure on the organic layers. The buffer layer between the printed cathode and the organic active layers, was fabricated by mixing the water/alcohol-soluble polymer poly[9,9-bis(3’-(N,N-dimethylamino)propyl)-2,7-fluorene-alt-2,7-(9,9-dioctylfluorene)] (PFNR2) and a curable epoxy adhesive. It offers the functions of solvent-proof, electron-injection, and proper affinity with the cathode ink. While improving the performance of devices, especially blocking the leakage current greatly, the cross-linked buffer layer also induces a novel phenomenon of ‘linear η-J plot’, which can be derived to interesting and realistic results. Red, green, and blue monochrome and full-color polymer light-emitting displays with a content format of 96 × 3 × 64 show neither dead pixels nor dead lines. Under optimized steps of curing, the nano silver ink forms continuous, defect-free, and low-resistance cathode rows without any distortion. The red, green, and blue displays exhibit the current efficiencies of 0.62, 4.38 and 0.93 cd/A, and CIE color coordinates of (0.63, 0.37), (0.39, 0.57) and (0.18, 0.16), respectively. The cathode printing technique removes the need of high vacuum for thermal evaporation of the cathode metal, which could lead to the industrial roll-to-roll process to manufacture the flat panel displays.
关键词： Buffer Layer,PLED,Printed Cathode,Display
更新于2025-09-23 15:21:21
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Electrochemical and Structural Investigation on Ultrathin ALD ZnO and TiO <sub/>2</sub> Coated Lithium-Rich Layered Oxide Cathodes
摘要： Ultrathin coatings (1.5 ± 0.3 nm) of titanium dioxide and zinc oxide were deposited on lithium-rich layered oxide cathodes (Li1.2Mn0.6Ni0.2O2, LLO) by atomic layer deposition (ALD). The structures, electrochemical performances, and thermal stabilities of these coatings were investigated. An ultrathin uniform coating was obtained for TiO2 but not for ZnO because of di?erences in the layer growth mechanism. Regarding the initial charge?discharge curves under a current density of 0.04 C rate, the TiO2 coated samples exhibited a higher discharge capacity, 242 mAhg?1, compared with the ZnO coated samples, 220 mAhg?1, or the pristine samples, 228 mAhg?1. Both coated samples exhibited more stable cycling performance and thermal stability than the pristine samples. After 80 cycles under 0.5 C rate, the TiO2 and ZnO coated samples were found to have higher capacity retention (～94% and 78%, respectively) than the pristine samples (68%). The reaction temperature of the exothermic peak of the TiO2 and ZnO coated samples at 4.8 V shifted to 280 °C with heat release of 88.7 J/g for TiO2 and 270 °C with heat release of 154.6 J/g for ZnO. This is compared with an exothermic peak at 258 °C with heat release of 253.5 J/g for the pristine sample. In particular, an enhanced rate capability was only observed for the TiO2 coated samples. When the current densities were higher than 2 C rate, the TiO2 coated samples exhibited superior capacities than the pristine and ZnO coated samples. At a current density of 5 and 10 C rate, the capacities were found to be 120 and 95 mAhg?1. The improved electrochemical performances were mainly attributed to lower resistance ?lm. This feature lead to more preactivation of the charge transfer, which resulted from the layer morphology of the TiO2 LLO, smoother electron transport, and suppression of more side reactions, when compared with the island structure of the ZnO ?lm.
关键词： ZnO,Cathode,Atomic layer deposition,Lithium-rich layered oxides,TiO2,Lithium ion battery
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Stability of carbon nanotube cold cathode electron beam (C-beam) with vacuum brazing process
摘要： A modularization of electronic parts in electrical devices is a key feature for system integration. Especially, x-ray tube fabrication process has been stayed in an obsolete manner due to the utilizing of classical thermionic x-ray sources. But cold cathode emitters such as carbon based materials with nanoscale dimension are expected to replace the conventional wired tungsten filaments due to their outstanding electrical and mechanical properties. To facilitate cold cathode emitter as an x-ray source, state of the arts bonding techniques are required. In this study, carbon nanotube grown Si wafers were successfully bonded to the metal carrier via vacuum brazing process and no electrical degradation of CNT (carbon nanotubes) emitters were observed after the process. Finally, we evaluated the stability of electron beam current density for device reliability. We expect that the cost-effective and facile technique could be applied for cold cathode based x-ray tube manufacturing process.
关键词： carbon nanotubes (CNTs),brazing,x-ray tube,junction,cold cathode
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Development of ultrafast electronic oscillator by exploiting advantage of cold cathodes
摘要： Origin of the upper frequency limit in vacuum devices was investigated. New analytical theory was developed for a simple vacuum diode in which electrons are launched on a cathode surface and are accelerated or decelerated toward an anode by a DC-biased AC electric field. We found electrons or charge carriers collectively arrives on the anode surface regardless of the frequency of the AC electric field if a diode configuration and the electric field are manipulated with some parameter values given by our theoretical calculations. The extraordinary collective behavior of electrons exceeds the transit-time limit which has given the upper frequency barrier in transitional electronic devices. For the novel electron devices, cold cathodes which emit electrons by the field emission is preferable to conventional thermionic cathodes because of the high nonlinearity between the current and the applied voltage. We are expanding the principle to develop a novel electronic oscillator that can operate in the terahertz frequency regime which demands ultrafast physical phenomenon.
关键词： ultrafast,vacuum device,cold cathode,electronic oscillator,transit-time limit
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Effect of thermal pre-treatment on thermionic emission current stability from carbon nanotube forests
摘要： Carbon nanotube forests have great potential as efficient thermionic electron emitters due to a highly localized optical heating effect (“Heat Trap”). In past experiments, we observed a rapid decay in the emission current. In this work, we demonstrate that a relatively stable emission current can be achieved if the nanotube forest is pre-heated to 300 °C for 4 hours priors to electron emission. We attribute this improved current stability to the removal of reactant species, such as water trapped within the nanotube forest network.
关键词： Heat Trap,outgassing,lifetime,Carbon nanotubes,current stability,cathode,thermionic emission
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - CNT field emitter based high performance x-ray source
摘要： We fabricated the cold cathode x-ray source composed of point-type CNT field emitter, mesh gate electrode, e-beam focusing lens and W anode. The point-type CNT field emitter was made by CNT film with a triangular tip shape. Field emission properties measured in triode configuration showed the low turn-on and threshold electric fields, the high emission current and focused electron beam spot. The CNT field emitter based cold cathode x-ray source reveals high resolution x-ray images. We demonstrated that the point-type CNT emitter is suitable candidate for the high performance cold cathode x-ray sources.
关键词： cold cathode x-ray source,triode structure,field emission,carbon nanotube filed emitter
更新于2025-09-23 15:21:21