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Vacuum Nanoelectronics Conference, 2007. IVNC. IEEE 20th International

Date 8-12 July 2007

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Displaying Results 1 - 25 of 123
  • Technical digest 20th International Vacuum Nanoelectronics Conference [Front and back cover]

    Publication Year: 2007 , Page(s): c1 - c4
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    Freely Available from IEEE
  • Program

    Publication Year: 2007
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  • Technical digest 20th international vacuum nanoelectronics conference July 8 –12, 2007

    Publication Year: 2007 , Page(s): i - vii
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (214 KB)  

    The following topics are dealt: vacuum nanoelectronics; carbon nanotube field emitter array applications; field emission cathode; field emission display; field emission mechanism characterisation; photoemission theory; ZnO nanostructured materials; novel emitter materials; XPS characterisation; field emission triode and MEMS. View full abstract»

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  • Author list

    Publication Year: 2007 , Page(s): 265 - 269
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    Freely Available from IEEE
  • Improvements on an out-of-plane MEMS quadrupole for portable mass spectrometry

    Publication Year: 2007 , Page(s): 2 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (507 KB) |  | HTML iconHTML  

    Quadrupoles are mass filters composed of a set of four cylindrical rods in a symmetrical setup that are biased with a combination of DC and RF potentials. There has been an active interest in developing scaled-down quadrupole technology for over a decade. This has led to remarkable results in both miniaturized and MEMS-based quadrupoles. This paper reports the design, fabrication, and characterization of a second generation of MEMS out-of-plane quadrupoles mass filter, part of a portable mass spectrometer for gas sensing. The mass spectrometer is composed of a CNT-based ionizer array, a MEMS quadrupole mass filter, MEMS electrometer for charge sensing, and a MEMS displacement pump that provides the required vacuum level. Two key advantages of scaling down quadrupoles are device portability and the relaxation on the vacuum level required for operation. For a fixed rod aspect ratio the quadrupole weight roughly scales to the cube of the rod diameter. Also, scaled down quadrupoles can work at higher pressure provided the gas mean free-path is larger than the quadrupole length. We have experimentally demonstrated that higher working pressure, up to the mTorr level, is compatible with our CNT-based electron impact and field ionizers with no loss in ionizer performance, thus setting the maximum quadrupole length at 5 cm. View full abstract»

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  • Fabrication and operation of triode electron emitters as ion source for miniature mass spectrometer

    Publication Year: 2007 , Page(s): 4 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2273 KB) |  | HTML iconHTML  

    The miniaturization of mass spectrometers should strengthen their usefulness in many applications as long as adequate performance is preserved. However, the use of laser-ionization or conventional filament-ionization sources severely hampered miniaturization of mass spectrometers, whereas triode electron emitters with carbon nanoparticle (CNP) film cathodes opened a new path towards realization of micro mass spectrometer since the fabrication of sufficiently small ion sources became possible using a conventional photolithography process. View full abstract»

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  • Hydrogen ion production using carbon nanotube field emitter arrays

    Publication Year: 2007 , Page(s): 6 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (115 KB) |  | HTML iconHTML  

    We have used micro-gated carbon nanotube field emitter arrays to produce hydrogen ions via two mechanisms; direct field ionization, and electron impact ionization. The changes in the fabrication process have improved the maximum emission current. The nanotubes are about 20nm in diameter (and so are likely multiwalled), and the gate electrodes are made of Cr. It is concluded that it should be possible to create very brief ion pulses using this method because the electron trajectory is short. Relatively long pulses will allow higher ionization rates. Because the arrays are small and the ion energy distribution is not too large, it should be possible to focus the ion beam to a spot size similar to the area of the array. View full abstract»

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  • AC performance of a novel carbon nanotube vacuum field emission differential amplifier IC

    Publication Year: 2007 , Page(s): 8 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    In this study, analytical modeling and AC measurements of the commom-mode rejection ratio (CMRR) of a single-chip carbon nanotube (CNT) vacuum field emission (VFE) differential amplifier (diff-amp) utilizing 2 mum conical-shaped CNT field emitter was presented. Dual-mask microfabrication process coupled with microwave plasma-enhanced chemical vapor deposition (MPCVD) growth of CNT emitters was employed to fabricate the matched VFE triode pairs with built-in split gates and integrated anodes to achieve a single-chip VFE diff-amp. View full abstract»

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  • Low-voltage field emitter array operation in cold cathode TWT

    Publication Year: 2007 , Page(s): 10 - 11
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (602 KB) |  | HTML iconHTML  

    The implementation of field emitter arrays as an electron beam source for TWTs has experienced some advancement in the past decade. The recent development of low-voltage Spindt field emitter arrays however has made possible operation at significantly reduced voltages, potentially improving emitter reliability and lifetime. As such, L-3 Electron Devices, teamed with SRI International, is developing a Field Emitter Array TWT (FEA-TWT) employing these new cathodes in order to evaluate their operation in the TWT vacuum environment, to investigate TWT design specific to use of field emitter arrays, and to quantify several aspects of FEA-TWT performance that will be substantially different than those of conventional thermionic-based TWTs. View full abstract»

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  • An injection locked millimeter wave oscillator based on field emission cathodes

    Publication Year: 2007 , Page(s): 12 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (177 KB) |  | HTML iconHTML  

    The frequency range of the millimeter wave is from 30 up to 300 GHz. Millimeter waves have been extensively studied for many applications including high resolution radars, communications, materials processing, plasma heating, high energy particle accelerators and power transmission. In this paper, an injection-locked millimeter wave oscillator based on field-emission cathodes is proposed and demonstrated the well phase/frequency controllability. The simulation results are consistent with the prediction of Adler's equation. The preliminary results show that the design of the injection-locked oscillator seems to promise useful and compact millimeter wave sources. View full abstract»

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  • Fabrication of field-emission cathode ray tube with an unique nano-structure carbon electron emitter

    Publication Year: 2007 , Page(s): 14 - 15
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (796 KB) |  | HTML iconHTML  

    In this study, a field-emission cathode ray tube (FE-CRT) has been fabricated using novel kind of electron emitter called carbon nano-exit (CNX) which has been developed on nickel, silicon and SUS substrate with a special plasma chemical vapor deposition (CVD) technique. Scanning electron microscopy(SEM) image indicates that the emitters have an array density of 2times108/cm2. View full abstract»

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  • Field emission display prototype using screen printed carbon nanotube cathode

    Publication Year: 2007 , Page(s): 16 - 17
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (473 KB) |  | HTML iconHTML  

    In this paper, mono-color and full-color FED prototypes of various sizes and resolutions have been fabricated. Video display has been demonstrated. The results show that the newly developed screen-printed CNT composite cathode is suitable for large area high resolution display application. View full abstract»

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  • Combined XPS/UPS/FES for characterisation of electron emission mechanism from diamond

    Publication Year: 2007 , Page(s): 18 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (234 KB) |  | HTML iconHTML  

    In this study, natural type lib diamond was used to characterise the origin of emitting electrons by the means of combined XPS/UPS/FES. Natural type lib diamond is one of the most intensively studied diamond due to its semiconductor properties and negative electron affinity (NEA) on hydrogenated (111) surface. The origin of emitting electrons from hydrogenated natural type lib diamond (111) surface, thus, can be a one of the most appropriate reference data for the future studies for diamond with various dopants and various surface terminations. View full abstract»

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  • XPS and LEED analyses on the extremely low work function surface of W(100) modified by yttrium oxide.

    Publication Year: 2007 , Page(s): 20 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (345 KB) |  | HTML iconHTML  

    XPS and LEED analyses have been done for tungsten (100) surface modified by use of Y2O3. No shift in Y-3d XPS peak is observed for heat treatment, suggesting that Y-O composite cannot be expected, in contrast to the case of ZrO/W(100) surface for which Zr-O composite is believed to exist. The particular LEED pattern is also different with each other: p(2X1) double domain pattern for YO/W(100) and c(4X2) double domain pattern for ZrO/W(100). View full abstract»

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  • Scanning atom probe study of graphite nanofibers

    Publication Year: 2007 , Page(s): 22 - 23
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (470 KB) |  | HTML iconHTML  

    Graphite nanofibers (GNF) were grown on a SUS304 needle by the thermal CVD method. Source gases were CO (50%) and H2 (50%) at 100 kPa, and growth temperature was 600 degC for 20 minutes. The SUS needle is mounted in the scanning atom probe (SAP) and mass analyzed by applying DC and pulsed voltages to the specimen at room temperature. The mass resolution m/Deltam of the SAP is better than 1000. The field emission characteristics are also examined by operating the SAP as a field emission microscope. View full abstract»

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  • Thermal-field treatment for creating single-crystal tungsten tips with ultimate sharpness

    Publication Year: 2007 , Page(s): 24 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (458 KB) |  | HTML iconHTML  

    The thermal-field (TF) treatment conditions for <111> oriented single-crystal tungsten tips were systematically studied using the remolding technique, which uses the reversely polarized field in the treatment opposite to the field emission polarity. A treatment sequence has been established for producing nanotips that end with a very sharp <111> apex at the end. View full abstract»

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  • Effect of radical oxygen gas exposure on Pt field emitter fabricated by electron-beam induced deposition

    Publication Year: 2007 , Page(s): 26 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB) |  | HTML iconHTML  

    The fabrication process of Pt field emitters with tip radii less than 10 nm and gate diameters ranging from 100 to 800 nm using focused ion beam (FIB) induced physical sputtering and EBID was developed. However, the Pt field emitter fabricated by EBID has an inherent issue of leakage current between the gate and cathode electrode due to the unwanted deposition at a gate insulator sidewall. Therefore the generation mechanism of leakage current and the decrease of leakage current of field emitters by a post treatment with radical oxygen gas exposure were studied. View full abstract»

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  • MWNT polymer composite degradation under high emission current regime as revealed by mass spectrometry

    Publication Year: 2007 , Page(s): 28 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB) |  | HTML iconHTML  

    In our work we study field emission properties of a new class of emitters formed by coating the MWNT-polymer composite film onto the flat metal substrate. MWNT-polystyrene suspension was coated onto the polished stainless steel tablets of 1 cm diameter by using spin-coating technique. In order to understand the physical and chemical processes for the composite emitter working regime we have elaborated the experimental technique combining mass spectrometry registration apparatus with the field emission unit, MSFEU. The technique enables to control both the composition and kinetics of gas release upon the emitter material degradation together with electron stimulated neutral molecule desorption from the anode. At present, this method is widely applied in various laboratories for studying the nature of the strength of solids. View full abstract»

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  • A new cold cathode using pulsed laser deposited lanthanum monosulfide thin films

    Publication Year: 2007 , Page(s): 32 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB) |  | HTML iconHTML  

    Using MEMS technology, an array of cold cathodes was fabricated by pulsed laser deposition (PLD) of chemically and thermally stable lanthanum monosulfide (LaS) thin film anode and cathode contacts. The latter were defined via etching and processing of two different pieces of (100) Si wafers separated via a highly resistive sputter deposited aluminum nitride (AlN) layer whose thickness was used to control the anode to cathode spacing. The top and bottom Si wafers were aligned and glued together using high temperature, vacuum compatible epoxy. Field emission (FE) characteristics were recorded in a vacuum chamber with a base pressure near 10-7 Torr. An average electric field threshold for Fowler-Nordheim (FN) field emission in the range of 100 V/mum was measured. A maximum current density of 8 mA/ cm2 was recorded which is large enough for flat panel display applications. The largest emission current measured was about 5X10-7 A above which thermal runaway occurred leading to a failure of the cathode. The failure mechanism is most likely due to Joule heating in the aluminum (Al) thin film underneath the LaS cathodes. View full abstract»

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  • Field desorption arrays for neutron generator ion sources

    Publication Year: 2007 , Page(s): 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (99 KB) |  | HTML iconHTML  

    The development of portable active neutron interrogation systems for field detection applications could be facilitated by the use of a novel microfabricated atomic deuterium ion source in compact, accelerator-driven neutron generators. This ion source uses field desorption from the tips of microfabricated field emitter-type arrays to produce atomic deuterium ions. The resulting generator design would have the unique characteristic of being easily scalable to provide the neutron outputs required to meet a wide variety of field detection needs. View full abstract»

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  • Measurements and analysis of advanced field emission cold cathodes

    Publication Year: 2007 , Page(s): 35 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB) |  | HTML iconHTML  

    We report measurements and analyses of field emission from both copper and aluminum cathodes. To analyze the data, we have developed a numerical model of electron emission. We note that localized heating of high current density field emission cathodes can provide regime where thermionic as well as field emission effects must be considered. Our analysis of experimental data fitting in both the thermionic and field emission dominant regime provides a robust method for determination of effective work function and field enhancement factor for field emission cathode. View full abstract»

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  • Development of a general thermal-field-photoemission model and its relation to current density, emittance, and beam brightness

    Publication Year: 2007 , Page(s): 42 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (147 KB) |  | HTML iconHTML  

    We have developed a methodology that combines the three emission mechanisms into one framework based on analytical, rather than numerical, methods. An account of the development shall be given. The approach demarcates "field-like" and "thermal-like" regimes dictated by which expansions of the current density integral dominate. Methods to regroup the expansions are shown, and the result exhibits a compelling symmetry as a function of the parameters used to characterize emission. The derivation of an equation for emittance and beam brightness from the methodology will be applied to a photocathode in particular. View full abstract»

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  • The physics of generalized Fowler-Nordheim-type equations

    Publication Year: 2007 , Page(s): 44 - 45
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    The aim here is to generalise the standard FN-type equation, so that the physical equation where the local emission current density (ECD) J is related to the barrier field F becomes clearer for metals. This is a preliminary need before the above equation can be fully linked with cold field electron emission (CFE) theory for non-metals. Each generalisation step needs stating in detail; this paper deals with the first few. View full abstract»

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  • Quantum interference depression in thin metal films with ridged surface

    Publication Year: 2007 , Page(s): 46 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (130 KB) |  | HTML iconHTML  

    We discuss what happens when low dimensional regular indents are fabricated on the surface of a thin metal film. Using corresponding theoretical methods, we study the free electron inside a potential-energy box with ridged wall and compare the results to the case with plane walls. It was shown that, ridged geometry of the wall leads to Quantum Interference Depression (QID), or reduction of the density of quantum states for the electron. Results obtained for the potential-energy box were extrapolated to the low-dimensional metals (thin metal films). QID leads to increase of the Fermi level and corresponding reduction of the work function. Experimental possibility of fabricating such indents on the surface of a thin metal film was studied. View full abstract»

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  • Modelling of electron transfer from a carbon nanotube cap into the vacuum under high extraction fields

    Publication Year: 2007 , Page(s): 48 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (207 KB) |  | HTML iconHTML  

    In the present work, we consider a system of a grounded CNT of length L and radius r0 (the emitter) facing a spherical anode of radius Ra(Ra>>r0). The anode is placed at some distance away from the emitter's tip. The CNT is modelled as a two-dimensional (2D) manifold where electrons behave as quasi-free and independent particle. The electrons are bound on the CNT surface by a one-dimensional (1D) potential well, due to the restriction imposed by the cylindrical symmetry. In order to have a full description of the electron behaviour in the whole system, a potential energy in the vacuum region needs also to be defined. To this purpose, the CNT cap is simplified as a grounded conducting sphere of radius r0 facing the anode on the same symmetry axis. As the emitter-anode distance, d and the anode radius, Ra are much greater than r0, the electric field in vacuum may be computed using the method of electrostatic images. View full abstract»

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