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Boron nitride nanotubes (BNNTs) have been studied as a field emission material due to their unique and excellent properties such as high oxidation resistance and negative electron affinity. However, field emission properties of BNNT field emitters were rarely reported until now because it is difficult to synthesize high purity BNNTs and fabricate stable BNNT field emitters. Here, we report high field...
Layered structured transition metal di-chalcogenides has attracted researchers as a substitute of graphene and its forms for various applications. In an attempt to explore field emission properties of these graphene analogues, synthesis and field emission behaviour of a few layered transition metal di-chalcogenides (TMDs) VS2, MoS2, MoO3 have been investigated at a base pressure of 1× 10−8 mbar. Furthermore,...
The case of an in-plane gated CNT emitter integrated in a planar diode configuration was investigated. An electrostatic model was proposed, which resulted in an analytical expression of the field at the apex of the CNT. Simulations validated this model and confirmed that the electrostatic influence of the bias electrode only depends on its radius and CNT height. The proximity of the gate as compared...
The coherent cold field emission (CCFE) images have been observed by a number of experiments. As the well-defined cold field nano-emitters such as carbon nanotubes and graphene can be implemented today, it is meaningful to discuss a microscopic theory for the CCFE. We will present a path-decomposition approach that incorporates the electronic structure of the nano-emitter and the emission wave function,...
In the paper, we examine the validity of traditional electron models (e.g. field emission, thermionic emission and photoemission) for graphene, and then propose new electron emission mechanisms and models to account for the unique properties of graphene. Also, some applications based on novel emission mechanism are explored.
In this paper, we report our recent works on modeling of ultrafast laser induce electron emission from a sharp tip and recent progress about space-charge-limited (SCL) current. We first study the pulse shape effect on electron emission by solving the time dependent Schrödinger equation. Carrier envelope phase effect is analyzed. Later we develop a single electron model to study the space charge (SC)...
Since the discovery of carbon nanotubes (CNTs), much attention has been paid to explore the use of one-dimensional nanomaterials as field emission electron cold cathodes. Now one may obtain electron emission at much low fields using the nano cold-cathodes and also can prepare vaccuum electron emitters in a self-assembly process. Many studies have been carried out in synthesis, characterization and...
This article reviews recent development of the vertically configured vacuum field emission integrated devices utilizing nanodiamond microtip emitters and their further implementation into circuits. The device design, fabrication and characterization of the nanodiamond vacuum field emission functional devices including transistor and triode are discussed. The realization of the basic circuit building...
Volcano-structured double-gate Spindt type field emitter arrays were fabricated using double-layered photoresist as a lift-off layer for the image sensor application. The emitter material that we tested is Ni and Mo/Ni. Electron beam focusing characteristics were evaluated by scanning slit method.
Silicon tip arrays were fabricated by means of reactive ion etching followed by oxidation for final sharpening and molybdenum thin film coating. The field-emission (FE) properties of these Mo-coated p-Si tip arrays were systemically investigated by different measurement techniques. Integral measurements in diode configuration yielded a turn-on field (for 1 nA) of 22 V/µm and nearly stable FE currents...
A novel development of combining the vacuum field-emission and nanoelectronic nanowire field-effect transistor technique in the photodetector application. In the report, Quantum Dots(QDs) are decorated onto reduced graphene oxide(RGO) fragments to overcome the low light photo responses(∼0.08A/W) of pristine graphene. In addition, exploiting high light absorption of quantum dots and RGO fragments,...
Field emission properties of various materials, primarily including carbon are actively investigated at the present time. The aim of this work is to study field emission properties of the beam of 3000 CF. Luminous flux for cathodoluminescence lamps with cathode based on studied carbon fibers with 15 W input power is up to 450 lm.
ZnO nanowires were treated with ammonia(NH3) plasma. Electrical and field emission properties of the same individual ZnO nanowire were investigated before and after NH3 plasma treatment. Lowered work function, increased resistance and lowered turn-on field was observed. Ammonia molecule substitutional defect on Zn site was attributed to the observed phenomena.
This conference poster reports two improved methods of extracting area-like information from measured current-voltage [im(Vm)] characteristics for cold field electron emission (CFE). Results are valid only if the emission situation is orthodox. These methods: (a) confirm “by experiment” the long-held theoretical expectation that in CFE theory the Schottky-Nordheim (SN) barrier is a better physical...
A photocathode based on n-doped graphene emitters in series to a GaAs photoswitch was fabricated and used for pulsed field electron emission. The n-doped graphene array emits at low turn-on fields (< 3 V/µm). A fast photomodulation of the emission current with high on/off ratio ∼200 was achieved with a semi-insulating (s.i.) GaAs photoswitch in a diode configuration. Different laser sources were...
Boron nanostructures (nanowires and nanotubes) have been thought as ideal nanomaterials for building optoelectronic nanodevices because of their high conductivity, large elastic modulus and high melting-point. In our studies, it is found that boron nanostructures have a low turn-on field and high emission uniformity. Moreover, boron nanostructures can endure a high emission current, which suggests...
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