Electron Emission Research Papers - Academia.edu (original) (raw)

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Recent papers in Electron Emission

Silicon is one of the most abundant materials which is used in many areas of modern research and technology. A variety of those applications require surface nanopatterning with minimum structure defects. However, the high-quality... more

Silicon is one of the most abundant materials which is used in many areas of modern research and technology. A variety of those applications require surface nanopatterning with minimum structure defects. However, the high-quality nanostructuring of large areas of silicon surface at industrially acceptable speed is still a challenge. Here, we report a rapid formation of highly regular laser-induced periodic surface structures (HR-LIPSS) in the regime of strong ablation by infrared femtosecond laser pulses at sub-MHz repetition rate. Parameters of the laser-surface interactions and obtained experimental results suggest an important role of electrostatically assisted bond softening in initiating the HR-LIPSS formation.

The behaviors of thermally stimulated electron emission from pyroelectric monodomain lithium niobate single crystal (LiNbO 3) were investigated by utilizing a Si p-n junction photodiode as electron detector and a receptive electron beam... more

The behaviors of thermally stimulated electron emission from pyroelectric monodomain lithium niobate single crystal (LiNbO 3) were investigated by utilizing a Si p-n junction photodiode as electron detector and a receptive electron beam resist (E-beam resist) as electron collector. In high vacuum (10 -6 Torr), the pyroelectric electron emission (PEE) was found to depend on the exposed emitting polar crystal surface (+ Z face or - Z face) and was significantly influenced by the emitter-electron receiver gap distances. Thus, the PEE from + Z face was detected during heating and was activated, in small gaps (<2 mm), by field emission effect on which was superposed an intense field ionization effect that primed intermittent runway ionizations (plasma breakdown into a glow discharge). In large gaps (>2 mm) the emission was simply mastered by field emission effect. Whereas, The PEE from - Z face was detected during cooling and was solely due to the field ionization effect. Therewith, for small gaps (<2 mm) the emission was governed by intermittent runway ionization ignitions resulting from a high ionization degree leading to dense plasma formation, and for large gaps (>2 mm) PEE was governed by field ionization generating a soft and continuous plasma ambient atmosphere. Significant decrease of electron emission current was observed from + Z face after successive thermal cycles. A fast and fully emission recovery was established after a brief exposure of crystal to a poor air vacuum of 10 -1 Torr.

The synchrotron radiation emitted from the NSLS VUV ring is found to contain significant spectral structure at long wavelengths (λ > 0.5mm), suggesting multiple beam interference effects. A predominant pattern occurs as a result of direct... more

The synchrotron radiation emitted from the NSLS VUV ring is found to contain significant spectral structure at long wavelengths (λ > 0.5mm), suggesting multiple beam interference effects. A predominant pattern occurs as a result of direct radiation interfering with radiation reflected from the curved outer wall of the electron beam dipole chambers. This structure appears for both normal incoherent synchrotron radiation emission and coherent emission, the latter resulting from an instability-driven density modulation within the electron bunch

This paper presents some fundamental characteristics and performance of a secondary emission electron gun (SEEG) using a pulsed glow discharge wire ion plasma source (WIPS). The positive helium ions extracted from WIPS are accelerated in... more

This paper presents some fundamental characteristics and performance of a secondary emission electron gun (SEEG) using a pulsed glow discharge wire ion plasma source (WIPS). The positive helium ions extracted from WIPS are accelerated in vacuum toward a negatively biased cold cathode surface, which is set oblique to the ion loci in order to inject the secondary electrons emitted perpendicular to the foil window. The physical mechanisms governing the characteristics such as space charge, charge exchange and secondary electron emission have been reviewed. The dependence of such characteristics on the accelerating voltage of the incident ion and on the ion incidence position has been experimentally investigated. The experimental results are discussed together with available theoretical models of each characteristic to establish the relative understanding of such phenomena in a side-extraction-type SEEG. The experimental results are further discussed in the light of a self-developed numerical simulation using a finite element method, which presents a good understanding of particle trajectories as well as potential distribution inside the gun geometry.

In this work we report on the fabrication of inductively coupled plasma (ICP) etched, diode-type, bulk molybdenum field emitter arrays. Emitter etching conditions as a function of etch mask geometry and process conditions were... more

In this work we report on the fabrication of inductively coupled plasma (ICP) etched, diode-type, bulk molybdenum field emitter arrays. Emitter etching conditions as a function of etch mask geometry and process conditions were systematically investigated. For optimized uniformity, aspect ratios of 410 were achieved, with 25.5 nm-radius tips realised for masks consisting of aperture arrays some 4.45 mm in diameter and whose field electron emission performance has been herein assessed.

Optical-field driven electron tunneling in nanojunctions has made demonstrable progress toward the development of ultrafast charge transport devices at subfemtosecond time scales, and have evidenced great potential as a springboard... more

Optical-field driven electron tunneling in nanojunctions has made demonstrable progress toward the development of ultrafast charge transport devices at subfemtosecond time scales, and have evidenced great potential as a springboard technology for the next generation of on-chip "lightwave electronics." Here, the empirical findings on photocurrent the high nonlinearity in metal-insulator-metal (MIM) nanojunctions driven by ultrafast optical pulses in the strong optical-field regime are reported. In the present MIM device, a 14th power-law scaling is identified, never achieved before in any known solid-state device. This work lays important technological foundations for the development of a new generation of ultracompact and ultrafast electronics devices that operate with suboptical-cycle response times.

Graphite conductive vertical microchannels, fabricated by femtosecond laser treatment, are proposed as distributed electrodes in defect-engineered (" black ") single-crystal diamond cathodes for innovative solar cells. Energy conversion... more

Graphite conductive vertical microchannels, fabricated by femtosecond laser treatment, are proposed as distributed electrodes in defect-engineered (" black ") single-crystal diamond cathodes for innovative solar cells. Energy conversion is based on photon-enhanced thermionic emission, where the reduction of the cathode series resistance is crucial to preserve conversion efficiency. Process yield higher than 80% and resistivity as low as 0.75 ± 0.15 U cm were achieved by the optimization of laser parameters and the use of a multi-pass writing technique. A 100 Â 100 array of graphite electrodes was integrated in a diamond-based cathode prototype, reducing the series resistance of more than 10 orders of magnitude with respect to bulk diamond.

We developed novel carbon-nanotube fi eld-emitter arrays (CNT-FEAs) with a resist-assisted patterning process using dc-plasma enhanced chemical vapor deposition (PECVD). Through this method, we obtained a CNT very strongly bonded to the... more

We developed novel carbon-nanotube fi eld-emitter arrays (CNT-FEAs) with a resist-assisted patterning process using dc-plasma enhanced chemical vapor deposition (PECVD). Through this method, we obtained a CNT very strongly bonded to the substrate. The CNTs were grown at -600 V bias to the substrate electrode and a +300 V bias to the mesh grid, being placed 10 mm above the substrate holder electrode. The structure and the electrical properties of the CNTs were strongly related to the growth time. The length was decreased after 80-minute and the diameter increased with the growth time. The electron emission current increased with growth time. The growth mechanism, the electron emission characteristics and the mechanical robustness are discussed.

Electronic and atomic relaxation processes in preirradiated solid Ar doped with N 2 were studied with a focus on the role of radiative electronic transitions in relaxation cascades. Combining methods of activation spectroscopy - thermally... more

Electronic and atomic relaxation processes in preirradiated solid Ar doped with N 2 were studied with a focus on the role of radiative electronic transitions in relaxation cascades. Combining methods of activation spectroscopy - thermally stimulated and photon-stimulated exoelectron emission, a new channel of relaxation induced by photon emission from metastable N atoms was detected. It was shown that in insulating materials with a wide conduction band photons of visible range can release electrons from both kinds of traps - shallow (lattice defects) and deep thermally disconnected ones. Correlation in the charge recombination reaction yield and the yield of low temperature desorption - important relaxation channel in a preirradiated solid - clearly demonstrates interconnection between atomic and electronic processes of relaxation.

Energetic (hot) electrons can be emitted from Al-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$-Au tunnel junctions. This emission supports a recently proposed hot-electron picture for light emission from tunnel junctions. A transfer ratio curve... more

Energetic (hot) electrons can be emitted from Al-${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$-Au tunnel junctions. This emission supports a recently proposed hot-electron picture for light emission from tunnel junctions. A transfer ratio curve shows that a fraction approaching 1% of the injected, hot tunneling electrons retain sufficient normal energy to surmount the Au-vacuum surface barrier and be collected if the Au work function is lowered by the evaporation of 3-4 monolayers of cesium. Fitting tunneling junction Iensuremath−VI\ensuremath{-}VIensuremath−V curves by two different methods gives a tunneling barrier 2-4 eV high and 15-19 \AA{} thick. These barrier parameters are comparable to those of light-emitting tunnel junctions.

Advance of technology touches most surely the area of marine engineering. Nanotechnology, as at the top of research interest, has potential to change our lives. Nanocomputers, nanocontrollers or nanomechanical devices will impact every... more

Advance of technology touches most surely the area of marine engineering. Nanotechnology, as at the top of research interest, has potential to change our lives. Nanocomputers, nanocontrollers or nanomechanical devices will impact every aspect of marine technology. One of the nanotechnological products are nano-electromechanical systems (NEMS). NEMS are manufactured and/or assembled by a lot of nanoelements. One of possible elements

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