Growth and patterning of aligned carbon nanotubes for applications to cold cathodes and vacuum electronics

The extremely large aspect ratio and sharp tips of carbon nanotubes made them among the most promising nanostructures for low-voltage and low-field cold cathode applications. The physically and chemically stable, highly thermally and electrically conductive carbon nanotubes allow very high density of electron current to be emitted without damages to the carbon nanotubes. By properly designing and growing carbon nanotubes and integrating them with 2-D and/or 3-D structures, high performance cold cathodes can be fabricated and applied to various vacuum electronics and vacuum power transferring applications. Well aligned carbon nanotubes have been grown using thermal chemical vapour deposition techniques and patterned into micro-structures by means of photolithographic techniques that are commonly used for silicon integrated circuit fabrication. Electron field emission at an average applied electric field of one volt per micrometer has been achieved. High current density cold cathodes fabricated on micro-patterned substrates as well as 3-D structures were investigated. In this presentation, the growth process, properties of carbon nanotubes, and their applications as cold cathodes for vacuum electronics will be discussed.