A fully sealed field-emission display 4.5 in. in size has been fabricated using single-wall carbon nanotube ͑CNT͒-organic binders. The fabricated displays were fully scalable at low temperature, below 415°C, and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1 V/m and field emission current of 1.5 mA at 3 V/m (J ϭ90 A/cm 2) were observed. Brightness of 1800 cd/m 2 at 3.7 V/m was observed on the entire area of a 4.5 in. panel from the green phosphor-indium-tin-oxide glass. The fluctuation of the current was found to be about 7% over a 4.5 in. cathode area.

Electromechanical switching devices have been fabricated successfully employing vertically grown multiwalled carbon nanotubes ͑MWCNTs͒ from the prepatterned catalyst dots on the patterned device electrodes. The devices show various interesting switching characteristics depending on the length and the number of MWCNTs used. The device design not only simplifies the fabrication process, but also improves the integration density greatly. The device has a great potential in realizing technically viable nanoelectromechanical systems, such as switch, memory, fingers, or grippers.

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The demand for increased information storage densities has pushed silicon technology to its limits and led to a focus on research on novel materials and device structures, such as magnetoresistive random access memory and carbon nanotube field-effect transistors, for ultra-large-scale integrated memory. Electromechanical devices are suitable for memory applications because of their excellent 'ON-OFF' ratios and fast switching characteristics, but they involve larger cells and more complex fabrication processes than silicon-based arrangements. Nanoelectromechanical devices based on carbon nanotubes have been reported previously, but it is still not possible to control the number and spatial location of nanotubes over large areas with the precision needed for the production of integrated circuits. Here we report a novel nanoelectromechanical switched capacitor structure based on vertically aligned multiwalled carbon nanotubes in which the mechanical movement of a nanotube relative to a carbon nanotube based capacitor defines 'ON' and 'OFF' states. The carbon nanotubes are grown with controlled dimensions at pre-defined locations on a silicon substrate in a process that could be made compatible with existing silicon technology, and the vertical orientation allows for a significant decrease in cell area over conventional devices. We have written data to the structure and it should be possible to read data with standard dynamic random access memory sensing circuitry. Simulations suggest that the use of high-k dielectrics in the capacitors will increase the capacitance to the levels needed for dynamic random access memory applications.

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Fabrication and characterization of a nanoelectromechanical switching device consisting of a suspended multiwalled carbon nanotube and self-aligned electrodes is reported. The device has a triode structure and is designed so that a suspended carbon nanotube is mechanically switched to one of two self-aligned electrodes by repulsive electrostatic forces between the nanotube and the other self-aligned electrode. Carbon nanotubes are dispersed on an SiO2 coated Si wafer and their locations recorded using a scanning electron microscope mapping process. Contact electrodes and self-aligned deflection electrodes are formed by a process comprising electron beam lithography, metallic thin film deposition, and lift-off. The electrical measurements show well-defined ON and OFF states with change of gate voltage. The measured threshold voltage for electromechanical switching is ∼3.6V.

Field emitter arrays with multiwall carbon nanotubes (CNTs) grown inside their gated holes were fabricated on glass substrates. The Fe–Ni–Co alloy catalyst dots on which the CNTs would be grown were deposited into the gated holes by a self-aligned method to maintain a constant distance between CNT emitters and gate electrodes. The CNTs were synthesized by thermal chemical vapor deposition using a gas mixture of CO and H2 at 500 °C. The CNT lengths were controlled by changing ratios of CO to H2. Field emission currents and images were monitored as a function of gate and anode voltages. It was shown that the CNT emitters grown just up to the gate electrode height operated best in a triode mode.

We have fabricated fully vacuum-sealed 5 in. diagonal carbon nanotube field-emission displays of a gated structure with reliable electron emission characteristics. Single-walled carbon nanotube tips were implemented into the gate structure using self-aligned backside exposure of photosensitive carbon nanotube paste. An onset gate electrode voltage for emission was about 60 V and the luminance as high as 510 cd/m2 was exhibited under an application of 100 V and 1.5 kV to gate electrode and anode, respectively.