Abstract: A field emission cathode device comprises a field emission cathode including a cylindrical substrate and a field emission material deposited on a cylindrical surface thereof. The field emission cathode defines a longitudinal axis. A solenoid extends concentrically about the cylindrical surface, and defines a gap therebetween. The solenoid defines opposed open ends perpendicular to the longitudinal axis. A current source directs a constant polarity (DC) current to the solenoid, that forms a magnetic field along the solenoid. A gate voltage source electrically connected to the solenoid or the field emission cathode interacts therewith to generate an electric field inducing the field emission cathode to emit electrons from the field emission material into the gap. The emitted electrons are responsive to the magnetic field to spiral within the gap and about the longitudinal axis, in correspondence with the current flow in the solenoid, through the first open end of the solenoid.

Abstract: A method for fabricating an electron field emission cathode, the field emission cathode including a substrate having a field emission material layer engaged therewith, where the field emission material incorporates a carbon nanotube material and a metal oxide. The field emission material is produced via a sol-gel process to improve field emission characteristics of the field emission cathode and field emission cathode devices implementing such cathodes.

Abstract: A field emission cathode device and method for forming a field emission cathode device involve a cathode element having a field emission surface, and a gate electrode element disposed in spaced-apart relation to the field emission surface of the cathode element so as to define a gap therebetween, with the gate electrode element having a plurality of parallel grill members or a mesh structure laterally-extending between opposing anchored ends. A film element laterally co-extends and is engaged with the gate electrode element, with the film element being arranged to allowed electrons emitted from the field emission surface of the cathode element to pass therethrough, and to cooperate with the gate electrode element and the cathode element to form a substantially uniform electric field within the gap and about the field emission surface.

Abstract: A method for fabricating a field emission cathode, the field emission cathode including a substrate having a field emission layer engaged therewith, where the field emission layer includes a plurality of purified carbon nanotubes. The carbon nanotubes are purified via a graphitization or annealing process.

Abstract: A field emission cathode device and formation method involves a rotating field emission cathode including a field emission material deposited on a surface thereof, the field emission cathode rotating about an axis and being electrically connected to ground, and a planar gate electrode extending parallel to the surface of the rotating field emission cathode and defining a gap therebetween. A gate voltage source is electrically connected to the gate electrode and is arranged to interact therewith to generate an electric field, with the electric field inducing a portion of the surface of the rotating field emission cathode adjacent to the gate electrode to emit electrons from the field emission material toward and through the gate electrode.

Abstract: A field emission cathode device and method for forming a field emission cathode device involve a cathode element having a field emission surface disposed in spaced-apart relation to a gate electrode element so as to define a gap between the field emission surface and the gate electrode element. The gate electrode element extends laterally between opposing anchored ends. The gate electrode element is arranged to deform away from the field emission surface in response to heat, so as to increase the gap between the field emission surface and the gate electrode element.

Abstract: A method for fabricating an electron field emission cathode, the field emission cathode including a substrate having a field emission material layer engaged therewith, where the field emission material incorporates a carbon nanotube material and a metal oxide. The field emission material is produced via a sol-gel process to improve field emission characteristics of the field emission cathode and field emission cathode devices implementing such cathodes.