The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Xiao Wei Sun - One of the best experts on this subject based on the ideXlab platform.
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efficient surface conducted Field Emission from zno nanotetrapods
Applied Physics Letters, 2007Co-Authors: Kai Hou, Wei Lei, Xiaobing Zhang, Baoping Wang, Xiao Wei SunAbstract:We report a surface-conducted Field Emission cathode using ZnO nanotetrapods as the surface conduction emitter. The dependences of electron Emission efficiency on ZnO nanotetrapod film thickness and the spacing between adjacent electrodes of surface emitter were studied. A maximum electron Emission efficiency of 60% was obtained for an optimal device with film thickness of 8μm and electrode spacing of 0.1mm. A low turn-on voltage of about 100V (corresponding to a Field of 1V∕μm) at an Emission current density of 0.6mA∕cm2 was obtained which is good enough for Field Emission displays. Good stability and uniformity were also demonstrated.
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stable Field Emission from hydrothermally grown zno nanotubes
Applied Physics Letters, 2006Co-Authors: A Wei, Xiao Wei Sun, Zhili Dong, Wei HuangAbstract:Zinc oxide nanotube arrays were prepared by hydrothermal reaction in ammonia and zinc chloride solutions, and the Field Emission properties were tested. The turn-on Field of the Field Emission was extrapolated to be about 7.0V∕μm at a current density of 0.1μA∕cm2. Meanwhile, the Emission current densities reached 1mA∕cm2 at a bias Field of 17.8V∕μm. The Field enhancement factor β was estimated to be 910. The Field Emission of the zinc oxide nanotubes showed good stability. The variation of Emission current density was less than 10% during a 24h test under a Field of 15V∕μm.
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Field Emission from gallium doped zinc oxide nanofiber array
Applied Physics Letters, 2004Co-Authors: Xiao Wei Sun, B J ChenAbstract:Gallium-doped nanostructural zinc oxide fibers have been fabricated by vapor-phase transport method of heating the mixture of zinc oxide, gallium oxide, and graphite powders in air. The zinc oxide fibers grew along [002] direction, forming a vertically aligned array that is predominantly perpendicular to the substrate surface. With a gallium doping concentration of 0.73 at. %, the corresponding carrier concentration and resistivity were 3.77×1020 cm−3 and 8.9×10−4 Ω cm, respectively. The Field Emission of these vertically aligned ZnO fiber arrays showed a low Field Emission threshold (2.4 V/μm at a current density of 0.1 μA/cm2), high current density, and high Field enhancement factor (2317). The dependence of Emission current density on the electric Field followed Fowler–Nordheim relationship. The enhanced Field Emission is attributed to the aligned structure, good crystal quality, and especially, the improved electrical properties (increased conductivity and reduced work function) of the nanofibers due ...
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Field Emission from zinc oxide nanopins
Applied Physics Letters, 2003Co-Authors: Xiao Wei SunAbstract:Nanostructural zinc oxide pins have been fabricated by vapor transport on copper-coated silicon wafer. The nanopins are composed of hexagonal wurtzite-phase zinc oxide with single crystal quality. The growth process includes two steps: (1) growth of a micron-sized zinc oxide dot on the substrate and (2) growth of a sharp tip from the zinc oxide dot. The Field Emission of the nanopins shows a low Field Emission threshold (1.92 V/μm at a current density of 0.1 μA/cm−2) and high current density with a Field enhancement factor of 657. The Emission current density and the electric Field follow Fowler–Nordheim relationship. The good performance for Field Emission is attributed to the single-crystalline structure and the nanopin geometry.
J Robertson - One of the best experts on this subject based on the ideXlab platform.
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effect of sp2 phase nanostructure on Field Emission from amorphous carbons
Applied Physics Letters, 2000Co-Authors: Adelina Ilie, A Ferrari, T Yagi, J RobertsonAbstract:Electron Field Emission from amorphous carbon is found to depend on the clustering of the sp2 phase. The size of the sp2 phase is varied by thermal annealing and it dominates the effect of other parameters, such as chemical composition, surface termination, sp3 content, or conductivity. The optimum size of the sp2 phase is determined by Raman spectroscopy and is of the order of 1 nm. The Field Emission originates from the sp2 regions and is facilitated by the large Field enhancement from more conductive sp2 clusters in an insulating sp3 matrix.
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Field Emission from tetrahedral amorphous carbon
Diamond and Related Materials, 1998Co-Authors: B S Satyanarayana, W I Milne, A Hart, J RobertsonAbstract:Abstract Field Emission from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum are has been measured. The threshold Field and current densities achievable have been studied as a function of their sp 3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold Field of 10–20 V μm −1 , decreasing with increasing sp 3 content, and optimally nitrogen-doped films exhibit threshold Fields as low as 3–5 V μm −1 .
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Field Emission from tetrahedral amorphous carbon
Applied Physics Letters, 1997Co-Authors: B S Satyanarayana, W I Milne, A Hart, J RobertsonAbstract:Field Emission has been measured from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum arc. The threshold Field and current densities achievable have been studied as a function of their sp3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold Field of 10–20 V/μm, decreasing with increasing sp3 content, and optimally nitrogen doped films exhibit threshold Fields as low as 3–5 V/μm.
W I Milne - One of the best experts on this subject based on the ideXlab platform.
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carbon nanotubes as Field Emission sources
Journal of Materials Chemistry, 2004Co-Authors: W I Milne, Kenneth B K Teo, G A J Amaratunga, Pierre Legagneux, L Gangloff, Jeanphilippe Schnell, V Semet, Thien V Binh, Oliver GroeningAbstract:Micro and nano-structurally rich carbon materials are alternatives to conventional metal/silicon tips for Field Emission sources. In particular, carbon nanotubes exhibit extraordinary Field Emission properties because of their high electrical conductivity, their high aspect ratio “whisker-like” shape for optimum geometrical Field enhancement, and remarkable thermal stability. This paper will review the PECVD growth process, and the microfabrication techniques needed to produce well defined carbon nanotube based micro-electron sources for use in novel parallel e-beam lithography and high frequency microwave amplifier systems.
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electrical and Field Emission investigation of individual carbon nanotubes from plasma enhanced chemical vapour deposition
Diamond and Related Materials, 2003Co-Authors: W I Milne, Kenneth B K Teo, G A J Amaratunga, Pierre Legagneux, Oliver Groening, Manishkumar Chhowalla, Seungbeck Lee, D G Hasko, H Ahmed, L GangloffAbstract:Abstract Plasma enhanced chemical vapour deposition (PECVD) is a controlled technique for the production of vertically aligned multiwall carbon nanotubes for Field Emission applications. In this paper, we investigate the electrical properties of individual carbon nanotubes which is important for designing Field Emission devices. PECVD nanotubes exhibit a room temperature resistance of 1–10 kΩ/μm length (resistivity 10 −6 to 10 −5 Ω m) and have a maximum current carrying capability of 0.2–2 mA (current density 10 7 –10 8 A/cm 2 ). The Field Emission characteristics show that the Field enhancement of the structures is strongly related to the geometry (height/radius) of the structures and maximum Emission currents of ∼10 μA were obtained. The failure of nanotubes under Field Emission is also discussed.
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Field Emission from dense sparse and patterned arrays of carbon nanofibers
Applied Physics Letters, 2002Co-Authors: Kenneth B K Teo, W I Milne, G A J Amaratunga, Pierre Legagneux, Manish Chhowalla, G Pirio, F Wyczisk, Didier Pribat, D G HaskoAbstract:We compare the Field Emission characteristics of dense (109 nanofibers/cm2), sparse (107 nanofibers/cm2), and patterned arrays (106 nanofibers/cm2) of vertically aligned carbon nanofibers on silicon substrates. The carbon nanofibers were prepared using plasma-enhanced chemical vapor deposition of acetylene and ammonia gases in the presence of a nickel catalyst. We demonstrate how the density of carbon nanofibers can be varied by reducing the deposition yield through nickel interaction with a diffusion layer or by direct lithographic patterning of the nickel catalyst to precisely position each nanofiber. The patterned array of individual vertically aligned nanofibers had the most desirable Field Emission characteristics, highest apparent Field enhancement factor, and Emission site density.
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Field Emission from tetrahedral amorphous carbon
Diamond and Related Materials, 1998Co-Authors: B S Satyanarayana, W I Milne, A Hart, J RobertsonAbstract:Abstract Field Emission from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum are has been measured. The threshold Field and current densities achievable have been studied as a function of their sp 3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold Field of 10–20 V μm −1 , decreasing with increasing sp 3 content, and optimally nitrogen-doped films exhibit threshold Fields as low as 3–5 V μm −1 .
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Field Emission from tetrahedral amorphous carbon
Applied Physics Letters, 1997Co-Authors: B S Satyanarayana, W I Milne, A Hart, J RobertsonAbstract:Field Emission has been measured from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum arc. The threshold Field and current densities achievable have been studied as a function of their sp3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold Field of 10–20 V/μm, decreasing with increasing sp3 content, and optimally nitrogen doped films exhibit threshold Fields as low as 3–5 V/μm.
J. Chen - One of the best experts on this subject based on the ideXlab platform.
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maximum Field Emission current density of cuo nanowires theoretical study using a defect related semiconductor Field Emission model and in situ measurements
Scientific Reports, 2018Co-Authors: Peng Zhao, Shao Zhi Deng, Ning Sheng Xu, Peng Ye, Yicong Chen, J. ChenAbstract:In this study, we proposed a theoretical model for one-dimensional semiconductor nanowires (NWs), taking account of the defect-related electrical transport process. The maximum Emission current density was calculated by considering the influence of Joule heating, using a one-dimensional heat equation. The Field Emission properties of individual CuO NWs with different electrical properties were studied using an in situ experimental technique. The experimental results for maximum Emission current density agreed well with the theoretical predictions and suggested that multiple conduction mechanisms were active. These may be induced by the concentration of defects in the CuO NW. The concentration of defects and the transport mechanisms were found to be key factors influencing the maximum Field Emission current density of the semiconductor NW. As is limited by the change of resistivity with temperature, only thermal runaway can trigger breakdown in CuO NWs.
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Pulse Field Emission characteristics of vertical few-layer graphene cold cathode
IEEE Transactions on Electron Devices, 2014Co-Authors: Yu Zhang, Shao Zhi Deng, Deliu Deng, Lijun Zhu, J. Chen, Ning Sheng XuAbstract:Vertical few-layer graphene (FLG) is an excellent Field Emission material, with an atomically thin edge and a 2-D heat dissipation area. A pulse voltage driving operation was used to achieve a high Field Emission current. The pulsewidth and duty ratio affected the Field Emission characteristics of the FLG due to the current heating effect. The optimal pulse parameters were obtained. A maximum current of 32 mA in 3-μs pulsing operation was achieved from a 5-mm diameter FLG film, which was 10 times greater than the maximum current achieved in continuous current operation. The current fluctuation was 4.1%. A method for further increasing the Emission current is proposed.
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growth and Field Emission property of tungsten oxide nanotip arrays
Applied Physics Letters, 2005Co-Authors: Jun Zhou, Shao Zhi Deng, Ning Sheng Xu, Li Gong, J. Chen, Rusen YangAbstract:Large-area, quasialigned nanotips of tungsten oxide have been grown by a two-step high-temperature, catalyst-free, physical evaporation deposition process. The tungsten oxide nanotips are single crystalline with growth direction of [010]. The tungsten oxide nanotips exhibit excellent Field-Emission properties with a low threshold Field (for an Emission current density of 10mA∕cm2) ∼4.37MV∕m and uniform Emission from the entire arrays, as well as high time stability. These results make tungsten oxide nanotip arrays a competitive candidate for Field-Emission displays.
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Field Emission from crystalline copper sulphide nanowire arrays
Applied Physics Letters, 2002Co-Authors: J. Chen, S. Z. Deng, Suhua Wang, Xiaogang Wen, Shihe Yang, Chunlei Yang, Jiannong WangAbstract:Straight crystalline copper sulphide (Cu2S) nanowire arrays have been grown by using a simple gas–solid reaction at room temperature. These were demonstrated to exhibit semiconductor properties. Field Emission was observed at a Field of ∼6 MV/m, and its current-Field characteristics deviate from Fowler–Nordheim theory, i.e., showing a nonlinear Fowler–Nordheim plot. The uniform Emission from the whole arrays was observed using transparent anode technique, and their variation with applied Field was recorded. The Emission from individual nanowires was also studied using a Field Emission microscope, and was found to consist of a number of spatially resolved diffuse spots. Finally, stable Emission current at different levels and over time was recorded. These findings indicate that semiconductor nanowires as cold cathode have a potential future, worthy of further comprehensive investigation. The technical importance of using semiconductor nanowires as cold cathode emitter is given.
B S Satyanarayana - One of the best experts on this subject based on the ideXlab platform.
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Field Emission from tetrahedral amorphous carbon
Diamond and Related Materials, 1998Co-Authors: B S Satyanarayana, W I Milne, A Hart, J RobertsonAbstract:Abstract Field Emission from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum are has been measured. The threshold Field and current densities achievable have been studied as a function of their sp 3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold Field of 10–20 V μm −1 , decreasing with increasing sp 3 content, and optimally nitrogen-doped films exhibit threshold Fields as low as 3–5 V μm −1 .
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Field Emission from tetrahedral amorphous carbon
Applied Physics Letters, 1997Co-Authors: B S Satyanarayana, W I Milne, A Hart, J RobertsonAbstract:Field Emission has been measured from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum arc. The threshold Field and current densities achievable have been studied as a function of their sp3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold Field of 10–20 V/μm, decreasing with increasing sp3 content, and optimally nitrogen doped films exhibit threshold Fields as low as 3–5 V/μm.
