Diamond and carbon nanotube coated cold cathodes for vacuum electronic applications

In this work, a technique is developed in order to control the morphology and alignment of the carbon nanotube coatings deposited using thermal chemical vapour deposition (CVD) method on various substrates. A Van der Pauw device is employed during the sputtering of the iron catalyst thin films to monitor the sheet resistance of the catalyst thin film. A relationship between the sheet resistance of the catalyst iron thin films and the alignment of the in situ grown carbon nanotubes is observed. The concentration of carbon content in the catalyst thin films is found to play an important role in the alignment of the carbon nanotubes by shortening or even eliminating the induction time, when the catalyst nanoparticles are saturated by carbon coming from the reactive carbon-containing gas, resulting in the simultaneous growth of the nanotubes. A mechanism of growing vertically aligned carbon nanotube coating is proposed based on above investigations.; Microcrystalline diamond, nanocrystalline diamond, and diamond-like carbon thin films are synthesized using liquid mixture of methanol and ethanol as feedstock in a microwave enhanced CVD apparatus. The electron field emission characteristics of those films are studied and compared with those of specimens synthesized using traditional methane/hydrogen gas mixtures in order to study the effect of the existence of oxygen in the reactive plasma on the electron field emission behaviors of the deposited thin films.; Carbon nanotube cold cathode is used as the source of triggering electrons for electrical gas breakdown. Glow discharge of argon gas is successfully triggered by the electrons emitted from a carbon nanotube coated cold cathode in a DC gas discharge system operated on the left-hand side of the Paschen curve. (Abstract shortened by UMI.)...