A stable high power carbon nanotube field-emitter device (original) (raw)

Field Emission with Ultralow Turn On Voltage from Metal Decorated Carbon Nanotubes

ACS Nano, 2014

A simple and scalable method of decorating 3D-carbon nanotube (CNT) forest with metal particles has been developed. The results observed in aluminum (Al) decorated CNTs and copper (Cu) decorated CNTs on silicon (Si) and Inconel are compared with undecorated samples. A significant improvement in the field emission characteristics of the cold cathode was observed with ultralow turn on voltage (E to ∼ 0.1 V/μm) due to decoration of CNTs with metal nanoparticles. Contact resistance between the CNTs and the substrate has also been reduced to a large extent, allowing us to get stable emission for longer duration without any current degradation, thereby providing a possibility of their use in vacuum microelectronic devices.

Fabrication of efficient field emitters with thin multiwalled carbon nanotubes using spray method

Carbon, 2006

Thin multiwalled carbon nanotube (t-MWCNTs)-based field emitters are made by use of a spray method. The number of tube walls is between 2 and 6, with the corresponding outer diameters between 3 and 6 nm. They were dispersed in dichloroethane and sprayed onto metal-deposited indium tin oxide glass. After heat treatment, they were found to be tightly adhered to metal electrode. Excellent field emission characteristics were exhibited, with a large field enhancement factor and low turn-on voltage, comparable to those of singlewalled CNTs. However, the t-MWCNTs demonstrated a significantly lower degradation rate than SWCNTs in the emission current. This high emission stability was attributed to their stable edge structures, similar to conventional large-diameter MWCNTs. Therefore, t-MWCNTs could be utilized as an alternative material for field emitters.

Carbon Nanotube Field Emission Devices with Integrated Gate for High Current Applications

2008 8th IEEE Conference on Nanotechnology, 2008

We present a fabrication technique for the integration of a gate electrode with an array of carbon nanotube (CNT) emitters. These gated cathode structures have high emission current density and may be utilized in X-ray tubes, traveling wave tubes, and ion propulsion systems. The CNT emitters are grown directly on polished bulk metal substrates and are comprised of CNT bundles that are vertically aligned and can be uniformly produced over a large substrate area. These arrays present many advantages including the capacity to sustain current densities greater than 60 mA/cm 2 and turn-on fields as low as 0.9 V/μm. We also present a detailed integration scheme utilizing these arrays of CNT emitters for the fabrication of gated cathode structures. Relative to other CNT emitters these gated structures have low operating voltages at higher emission current densities. Finite element analysis is used to investigate the electrostatic properties of both gated and ungated pillar structures. These results demonstrate that the benefits afforded by CPAs can be further enhanced by the addition of an integrated gate electrode.

A high-performance triode-type carbon nanotube field emitter for mass production

Nanotechnology, 2007

A triode-type field emission device based on carbon nanotubes (CNTs) synthesized on an anodic aluminum oxide (AAO) template was fabricated. For the improvement of device performance, in addition to the basic advantages of using AAO to obtain uniform CNTs with strong adhesion, several considerations were taken into account, including highly crystalline CNTs synthesized through thermal chemical vapor deposition (CVD) at 1200 • C, lowering the contact resistance with a Ti buffer layer and reducing the pixel size and gate-to-emitter distance. The triode-type field emitter showed a high current density of 20 mA cm −2 and a low turn-on voltage of 16 V. The very high field enhancement factor of 1.6 × 10 6 cm −1 confirmed the high efficiency of the triode structure in electron extraction.

Fabrication of Carbon Nanotube Field Emitters Using a Dip-Coating Method

Chemical Vapor Deposition, 2006

A simple and robust dip-coating method for fabricating carbon nanotube (CNT) field emitters has been proposed. The thin multiwalled (tMW)CNTs synthesized by CVD were dispersed in various solutions such as N,N-dimethylformamide (DMF), isopropyl alcohol (IPA), N-methyl-2-pyrrolidinone (NMP), and dichloroethane (DCE). The weak adhesion between CNTs and substrate, a serious drawback of the dip-coating approach, was resolved by anchoring CNTs to the substrate via the melting of an indium layer. We found that the uniformity and density of the CNTs could be optimized by controlling the degree of dispersion of CNTs in solvents. The field-emission characteristics are also discussed.

Towards a low-cost high-quality carbon-nanotube field-emission display

Journal of the Society for Information Display, 2004

We have developed field-emission-display technology driven by chemical-vapordeposition-grown carbon-nanotube emitters incorporated in a simple, low-cost device structure. Here, we report on frit-sealed test displays with a brightness of 3000 cd/m 2 at 3 kV and a lifetime of 9000 hours with only 45% degradation. We also demonstrate the scalability of the technology with a uniform high-brightness 6-in. QVGA that displays video images with a switching voltage of 40 V. FIGURE 1 -Cross section of the cathode structure.

Field Emission Properties of Single-Walled Carbon Nanotubes with a Variety of Emitter Morphologies

Japanese Journal of Applied Physics, 2008

Field emission properties of single-walled carbon nanotubes (SWCNTs), which were prepared through alcohol catalytic chemical vapor deposition for 10 -60 s, were characterized in a diode configuration. Protrusive bundles at the top surface of samples act selectively as emission sites. The number of emission sites was controlled by emitter morphologies combined with texturing of Si substrates. SWCNTs grown on a textured Si substrate exhibited a turn-on field as low as 2.4 V/mm at a field emission current density of 1 mA/cm 2 . Uniform spatial luminescence (0.5 cm 2 ) from the rear surface of the anode was revealed for SWCNTs prepared on the textured Si substrate. Deterioration of field emission properties through repetitive measurements was reduced for the textured samples in comparison with vertically aligned SWCNTs and a random network of SWCNTs prepared on flat Si substrates. Emitter morphology resulting in improved field emission properties is a crucial factor for the fabrication of SWCNT-electron sources. Morphologically controlled SWCNTs with promising emitter performance are expected to be practical electron sources.