Carbon nanotube cathode research at AFRL

Summary form only given, as follows. Single-wall and multi-wall nanotubes have shown some promise as field emission cathodes. Most applications have focused on small surface areas with such uses as flat panel displays. The Air Force Research Laboratory has begun to investigate the uses of these cathodes for larger areas. Several types of nanotube cathodes have been investigated. Each type is implemented in a 63 cm/sup 2/ circular geometry. The first consists of single wall nanotubes deposited on a molybdenum substrate. The second consists of single wall nanotubes deposited on a novel carbon substrate. These cathodes are compared to existing large area field emission cathodes such as polymer velvet. We contrast the performance of each relative to the required figures of merit for existing field emission structures as well as existing thermal cathodes.