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Field Emission (field + emission)
Kinds of Field Emission Terms modified by Field Emission Selected AbstractsFabrication of Large-Scale Single-Crystalline PrB6 Nanorods and Their Temperature-Dependent Electron Field EmissionADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Qin Yuan Zhang Abstract A simple catalysis-free approach that utilises a gas,solid reaction for the synthesis of large-scale single-crystalline PrB6 nanorods using Pr and BCl3 as starting materials is demonstrated. The nanorods exhibit a low turn-on electric field (2.80,V µ-b;m,1 at 10,µ-b;A cm,2), a low threshold electric field (6.99,V µ-b;m,1 at 1,mA cm,2), and a high current density (1.2,mA cm,2 at 7.35,V µ-b;m,1) at room temperature (RT). The turn-on and threshold electric field are found to decrease clearly from 2.80 to 0.95 and 6.99 to 3.55,V µ-b;m,1, respectively, while the emission current density increases significantly from 1.2 to 13.8,mA cm,2 (at 7.35,V µ-b;m,1) with an increase in the ambient temperature from RT to 623,K. The field enhancement factor, emission current density, and the dependence of the effective work function with temperature are investigated. The possible mechanism of the temperature-dependent emission from PrB6 nanorods is discussed. [source] Field Emission and Cathodoluminescence of ZnS Hexagonal Pyramids of Zinc Blende Structured Single CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Zhi-Gang Chen Abstract Single-crystal hexagonal pyramids of zinc blende ZnS are fabricated by facile thermal evaporation in an ammonia atmosphere at 1150,°C. It is found that ZnS pyramids grow along the [111] crystal axis and possess a sharp tip with a diameter of ,10,nm and a micrometer-sized base. The structural model and growth mechanism are proposed based on crystallographic characteristics. This unique ZnS pyramid structure exhibits a low turn-on field (2.81,V µm,1), a high field-enhancement factor (over 3000), a large field-emission current density (20,mA cm,2), and good stability with very small fluctuation (0.9%). These superior field-emission properties are clearly attributed to the pyramid morphology, with micrometer-sized bases and nanotips, and high crystallinity. Moreover, a stable UV emission of 337,nm at room temperature is observed and can be ascribed to the band emission of the zinc blende phase. These results suggest that the ZnS hexagonal pyramids can be expected to find promising applications as field emitters and optoelectronic devices. [source] Field Emission of Single-Layer Graphene Films Prepared by Electrophoretic DepositionADVANCED MATERIALS, Issue 17 2009Zhong-Shuai Wu Homogeneous single-layer graphene films are fabricated using an electrophoretic deposition technique, and their field-emission properties are investigated. The graphene films show high density, uniform thickness, numerous edges normal to the film surface, and good interface contact and adhesion with the substrate, and consequently show excellent field-emission properties. [source] Electron Field Emission and Photoluminescence of Anatase Nanotube ArraysJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2008Yang Yang TiO2 nanotube arrays with a high aspect ratio were grown on conductive Ti substrates by anodization in an organic electrolyte. The as-prepared TiO2 nanotubes were vertically grown and adhered well to the substrates. The photoluminescence spectrum and X-ray diffraction showed that the crystal structure of the postannealed TiO2 nanotube arrays was oxygen-defective anatase. This kind of anatase nanotube arrays exhibited efficient electron field emission even at room temperature with a low applied electric field of ,9 V/,m. The emission current exceeded 70 ,A/cm2 at an extraction voltage of 700 V. [source] Field emission from surface-modified heavily phosphorus-doped homoepitaxial (111) diamondPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2007Takatoshi Yamada Abstract Field emission from heavily phosphorus-doped homoepitaxial (111) diamonds after surface modifications are discussed. To develop a model for emission, we applied X-ray photoelectron spectroscopy (XPS) to characterize surface properties of H-plasma treated, oxidized and carbon-reconstructed surfaces. In addition, reflection high energy electron diffraction (RHEED) is used to evaluate atomic arrangements. Atomic force microscopy (AFM) is used to investigate surface morphologies. From AFM, no major difference is observed between H-terminated, oxidized and carbon reconstructed surfaces. Field emission proper- ties of carbon reconstructed surfaces show a lower threshold than hydrogen-terminated or oxidized surfaces. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Field emission from single-wall nanotubes obtained from carbon and boron nitride mixturesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2008V. I. Kleshch Abstract Heterophase BN:C single-wall nanotubes are prospective as a material with a predicted possibility to vary the bandgap via changing a relative content of BN and C fractions in the nanotube walls. The challenge is both to find the ways of synthesis of such nanotubes and, in case of success, to confirm BN embedding. In this work field emission studies have been performed for revealing the difference between arc-produced pure carbon nanotubes and nanotubes grown from BN:C mixtures. The relative BN content in the mixtures was varied from 0% up to 50% (by mass). The materials have been characterized by a high resolution transmission electron microscopy, Raman scattering and UV-VIS-NIR optical absorption techniques. The single-wall nanotubes have been revealed in all samples synthesized, but their composition remained questionable. The field emission properties of the samples have been examined in a vacuum diode configuration. It has been found that the threshold fields and slopes of the Fowler,Nordheim plot, evaluated from the measured current,voltage dependences, increased with an enrichment of the starting mixtures with h-BN. This increase could be attributed to the work function rise due to h-BN embedding into the carbon nanotube walls. This result opens a way to use the field-emission characterization for an indirect confirmation of the heterophase BN:C nanotube formation. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Coupled nonlinear effects in modeling field emission from CNTsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2007R.V.N. Melnik Field emission from carbon nanotubes (CNTs) is a complex process involving a range of physical effects and phenomena. In this paper, we systematically develop a multiphysics model to describe this process. We integrate the model numerically to estimate the output current from a CNT based field emission device. Numerical simulations have been able to capture the transients in current as observed in actual experiments. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrochemically Tuned Properties for Electrolyte-Free Carbon Nanotube SheetsADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Alexander A. Zakhidov Abstract Injecting high electronic charge densities can profoundly change the optical, electrical, and magnetic properties of materials. Such charge injection in bulk materials has traditionally involved either dopant intercalation or the maintained use of a contacting electrolyte. Tunable electrochemical charge injection and charge retention, in which neither volumetric intercalation of ions nor maintained electrolyte contact is needed, are demonstrated for carbon nanotube sheets in the absence of an applied field. The tunability of electrical conductivity and electron field emission in the subsequent material is presented. Application of this material to supercapacitors may extend their charge-storage times because they can retain charge after the removal of the electrolyte. [source] ZnS Branched Architectures as Optoelectronic Devices and Field EmittersADVANCED MATERIALS, Issue 21 2010Zhi-Gang Chen A unique ZnS branched architecture was fabricated by a facile thermal evaporation method. Stable UV emission at 327,nm and superior field emission with a low turn-on field, a high field-enhancement factor, a large current density, and small fluctuation were observed. [source] Electron Field Emission and Photoluminescence of Anatase Nanotube ArraysJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2008Yang Yang TiO2 nanotube arrays with a high aspect ratio were grown on conductive Ti substrates by anodization in an organic electrolyte. The as-prepared TiO2 nanotubes were vertically grown and adhered well to the substrates. The photoluminescence spectrum and X-ray diffraction showed that the crystal structure of the postannealed TiO2 nanotube arrays was oxygen-defective anatase. This kind of anatase nanotube arrays exhibited efficient electron field emission even at room temperature with a low applied electric field of ,9 V/,m. The emission current exceeded 70 ,A/cm2 at an extraction voltage of 700 V. [source] Impact of n-type doping on the terahertz surface emission from c -plane InNPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2010V. M. Polyakov Abstract We theoretically investigate the influence of n-type doping on the terahertz (THz) electric field emission from unbiased c -plane InN surfaces using the ensemble Monte Carlo (MC) method. It is shown that the increase of n-type doping has twofold effect on the THz surface emission. The detrimental effect of electron drift mobility decrease is compensated by doping-derived electrons constructively contributing to the total dynamic dipole responsible for a generation of the THz electric field pulse emission from InN surface. [source] Coupled nonlinear effects in modeling field emission from CNTsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2007R.V.N. Melnik Field emission from carbon nanotubes (CNTs) is a complex process involving a range of physical effects and phenomena. In this paper, we systematically develop a multiphysics model to describe this process. We integrate the model numerically to estimate the output current from a CNT based field emission device. Numerical simulations have been able to capture the transients in current as observed in actual experiments. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||