Application of field emitter arrays to microwave power amplifiers

Spindt, C.A.; Armstrong, C.M.; Smith, C.R.; Gannon, Benjamin M.; Whaley, D.R.

doi:10.1109/27.887712

Cited by 148 publications

(15 citation statements)

References 39 publications

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“…The model will be useful to serve as the upper limit or maximum current emission allowed for different cathodes using sharp tip or protrusive structures in various applications. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] FIG . 4.…”

Section: Discussionmentioning

confidence: 98%

“…Due to the contemporary needs on the studies of nanogaps and short electron bunches, this 1D classical CL law has been extended to various regimes, including multi-dimensions, [3][4][5][6][7] quantum regime, 8,9 short pulse limit, 10,11 single-electron limit, 12 new scaling in other geometries 13 with applications in THz source 14,15 and time dependent current injection. [16][17][18] Electron emission from a sharp tip is important for many applications, such as vacuum microelectronics, 19 compact high current cathodes for high power microwave sources, [20][21][22] ultrafast laser induced electron emission from sharp tip, [23][24][25][26][27] ultrafast electron imaging, [28][29][30] laser-driven dielectric acceleration, 31,32 and high brightness photo-cathode 33,34 for X-ray free electron laser (FEL). For electron emission from a sharp tip, the localized electron density near to the tip is very high, which induces a space charge electric field, strong enough to modify the external applied electric field significantly, and thus to influence the field emission process.…”

Section: Introductionmentioning

confidence: 99%

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Space charge limited current emission for a sharp tip

Zhu

Ang

2015

Physics of Plasmas

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In this paper, we formulate a self-consistent model to study the space charge limited current emission from a sharp tip in a dc gap. The tip is assumed to have a radius in the order of 10s nanometer. The electrons are emitted from the tip due to field emission process. It is found that the localized current density J at the apex of the tip can be much higher than the classical Child Langmuir law (flat surface). A scaling of J / V g 3/2 /D m , where V g is the gap bias, D is the gap size, and m ¼ 1.1-1.2 (depending on the emission area or radius) is proposed. The effects of non-uniform emission and the spatial dependence of work function are presented. V C 2015 AIP Publishing LLC.

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Space charge limited current emission for a sharp tip

Zhu

Ang

2015

Physics of Plasmas

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“…Such a model treats surface roughness as more nuisance than desideratum in characterizing the influence of roughness on the current that can be drawn across a diode configuration. When field emission is desired, the emitters are more conical 48,49 or wire-like. 9,50 Shielding is therefore dependent on the character of the emitter itself and shall be taken up separately.…”

Section: Unit Cell Space Chargementioning

confidence: 99%

Discrete space charge affected field emission: Flat and hemisphere emitters

Jensen

Shiffler

Rittersdorf

et al. 2015

Journal of Applied Physics

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Models of space-charge affected thermal-field emission from protrusions, able to incorporate the effects of both surface roughness and elongated field emitter structures in beam optics codes, are desirable but difficult. The models proposed here treat the meso-scale diode region separate from the micro-scale regions characteristic of the emission sites. The consequences of discrete emission events are given for both one-dimensional (sheets of charge) and three dimensional (rings of charge) models: in the former, results converge to steady state conditions found by theory (e.g., Rokhlenko et al. [J. Appl. Phys. 107, 014904 (2010)]) but show oscillatory structure as they do. Surface roughness or geometric features are handled using a ring of charge model, from which the image charges are found and used to modify the apex field and emitted current. The roughness model is shown to have additional constraints related to the discrete nature of electron charge. The ability of a unit cell model to treat field emitter structures and incorporate surface roughness effects inside a beam optics code is assessed. V C 2015 AIP Publishing LLC.

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“…(2) and (3)] (blue diamonds), with the empirical formula [Eqs. (4)] (black solid line). Note that as L !…”

Section: Theory and Modelingmentioning

confidence: 99%

“…[1][2][3][4][5] It is well known that the proximity of the individual field emitter in the array leads to electric field screening, which in turn affects the amount of current that can be liberated from the cathode surface. While this paper presents new results, electric field screening due to the proximity of individual field emitters were featured prominently in many previous studies.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of electric field screening by the proximity of two carbon fiber cathodes

Tang

Shiffler

Golby³

et al. 2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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This paper describes the first experiments that use only two carbon fiber field emitters with different separations to quantify and isolate the effect of electric field screening. Experiments show that when the separation between the two carbon fiber cathodes decreases, both the effective field enhancement factor, βeff, and the current emission decreases. For a two-emitter geometry, our experiment suggests a height of approximately 1.5 times the separation between the two cathodes as the optimum ratio to optimize the emitted current. The paper shows the analysis of the turn on voltage of the field emitters for different separations. The authors compare experimental data with Fowler–Nordheim field emission theory and particle-in-cell simulation, showing good agreement between experiment, theory, and modeling.

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Application of field emitter arrays to microwave power amplifiers

Cited by 148 publications

References 39 publications

Space charge limited current emission for a sharp tip

Space charge limited current emission for a sharp tip

Discrete space charge affected field emission: Flat and hemisphere emitters

Experimental study of electric field screening by the proximity of two carbon fiber cathodes

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