Abstract:
Electron emitters and methods of fabricating the electron emitters are disclosed. According to certain embodiments, an electron emitter includes a tip with a planar region having a diameter in a range of approximately (0.05-10) micrometers. The electron emitter tip is configured to release field emission electrons. The electron emitter further includes a work-function-lowering material coated on the tip.
Abstract:
A carbon nanotube micro-tip structure includes an insulating substrate and a patterned carbon nanotube film structure. The insulating substrate includes a surface. The surface includes an edge. The patterned carbon nanotube film structure is partially arranged on the surface of the insulating substrate. The patterned carbon nanotube film structure includes two strip-shaped arms joined at one end to form a tip portion protruded from the edge of the surface of the insulating substrate and suspended. Each of the two strip-shaped arms includes a plurality of carbon nanotubes parallel to the surface of the insulating substrate.
Abstract:
A system in accordance with the invention which generates electrons by means of a field-emission cathode comprises an array of electron-emitting micropoints associated with a grid and carried by a substrate with integral heater means for heating the micropoints to a temperature in the range approximately 300° C. to approximately 400° C. and maintaining them at that temperature during emission of electrons. The cathode can therefore function at higher residual air pressures with no risk of breakdown.
Abstract:
An array of carbon nanotube micro-tip structure includes an insulating substrate and a plurality of patterned carbon nanotube film structures. The insulating substrate includes a surface. The surface includes an edge. A plurality of patterned carbon nanotube film structures spaced from each other. Each of the plurality of patterned carbon nanotube film structures is partially arranged on the surface of the insulating substrate. Each of the plurality of patterned carbon nanotube film structures comprises two strip-shaped arms joined together forming a tip portion protruding and suspending from the edge of the surface of the insulating substrate. Each of the two strip-shaped arms comprises a plurality of carbon nanotubes parallel to the surface of the insulating substrate.
Abstract:
Provided is a Schottky emitter having the conical end with a radius of curvature of 2.0 μm on the emission side of an electron beam. Since a radius of curvature is 1 μm or more, a focal length of an electron gun can be longer than in a conventional practice wherein a radius of curvature is in the range of from 0.5 μm to not more than 0.6 μm. The focal length was found to be roughly proportional to the radius of the curvature. Since the angular current intensity (the beam current per unit solid angle) is proportional to square of the electron gun focal length, the former can be improved by an order of magnitude within a practicable increase in the emitter radius. A higher angular current intensity means a larger beam current available from the electron gun and the invention enables the Schottky emitters to be used in applications which require relatively high beam current of microampere regime such as microfocus X-ray tube, electron probe micro-analyzer, and electron beam lithography system.
Abstract:
An exemplary electron emission device includes an electron emitter, an anode opposite to and spaced apart from the electron emitter, a first power supply circuit, and a second power supply circuit. The first power supply circuit is configured for electrically connecting the electron emitter and the anode with a power supply to generate an electric field between the electron emitter and the anode. The second power supply circuit is configured for electrically connecting the electron emitter with a power supply to supply a heating current for heating the electron emitter whereby electrons emit therefrom. Methods for generating an emission current with a relatively higher stability also are provided.
Abstract:
A thermionic electron source includes a substrate, two electrodes, and a thermionic emitter. The thermionic emitter is electrically connected to the two electrodes. The substrate has a recess formed on a surface thereof, and the thermionic emitter is located on the surface of the substrate corresponding to the recess.
Abstract:
An electron source is made from mixed-metal carbide materials of high refractory nature. Producing field-enhanced thermionic emission, i.e., thermal-field or extended Schottky emission, from these materials entails the use of a certain low work function crystallographic direction, such as, for example, (100), (210), and (310). These materials do not naturally facet because of their refractory nature. The disclosed electron source made from transition metal carbide material is especially useful when installed in a scanning electron microscope (SEM) performing advanced imaging applications that require a high brightness, high beam current source.
Abstract:
A thermionic electron source includes a substrate, two electrodes, and a thermionic emitter. The thermionic emitter is electrically connected to the two electrodes. The substrate has a recess formed on a surface thereof, and the thermionic emitter is located on the surface of the substrate corresponding to the recess.
Abstract:
An exemplary electron emission device includes an electron emitter, an anode opposite to and spaced apart from the electron emitter, a first power supply circuit, and a second power supply circuit. The first power supply circuit is configured for electrically connecting the electron emitter and the anode with a power supply to generate an electric field between the electron emitter and the anode. The second power supply circuit is configured for electrically connecting the electron emitter with a power supply to supply a heating current for heating the electron emitter whereby electrons emit therefrom. Methods for generating an emission current with a relatively higher stability also are provided.