At least one emitter formed of an electron emissive material is positioned on a cathode assembly and is readily and reliably connected to at least one mounting member of the cathode assembly. The connections between the at least one emitter and an emitter support structure are formed directly between the at least one emitter and the emitter support structure by utilizing the at one mounting member on the emitter support structure that are positioned adjacent the at least one emitter and heated to secure the at least one emitter to the emitter support structure by welding the at least one mounting member to the at least one emitter and emitter support structure.

A thermionic emission device comprises a first electrode, a second electrode, a single carbon nanotube, an insulating layer and a gate electrode. The gate electrode is located on a first surface of the insulating layer. The first electrode and the second electrode are located on a second surface of the insulating layer and spaced apart from each other. The carbon nanotube comprises a first end, a second end opposite to the first end, and a middle portion located between the first end and the second end. The first end of the carbon nanotube is electrically connected to the first electrode, and the second end of the carbon nanotube is electrically connected to the second electrode.

A current CMOS technology compatible process to create a planar gate-insulated vacuum channel semiconductor structure. In one example, the structure is created on highly doped silicon. In another example, the structure is created on silicon on insulator (SOI) over a box oxide layer. The planar gate-insulated vacuum channel semiconductor structure is formed over a planar complementary metal-oxide-semiconductor (CMOS) device with a gate stack and a tip-shaped SiGe source/drain region. Shallow trench isolation (STI) is used to form cavities on either side of the gate stack. The cavities are filled with dielectric material. Multiple etching techniques disclosed creates a void in a channel in the tip-shaped SiGe source/drain region under the gate stack. A vacuum is created in the void using physical vapor deposition (PVD) in a region above the tip-shaped SiGe source/drain regions.

A filament assembly can include: a button having a planar emitter region with one or more apertures extending from an emission surface of the planar emitter region to an internal surface opposite of the emission surface; an inlet electrical lead coupled to the button at a first side; an outlet electrical lead coupled to the button at a second side opposite of the first side; and a low work function object positioned adjacent to the internal surface of the planar emitter region and retained to the button. The planar emitter region can include a plurality of apertures. The low work function object can include a porous ceramic material having the barium, and may have a polished external surface. An electron gun can include the filament assembly. An additive manufacturing system can include the electron gun having the filament assembly.

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.

According to one embodiment, an X-ray tube, including a cathode including a filament including a leg portion extending from a coil to a distal portion and including a corner portion at the distal portion, a support terminal including a gap, and including an opening portion in which the gap is opened and a bottom portion located on a side opposite to the opening portion, and a cathode cup being connected to the support terminal, the distal portion being located in the gap, the support terminal including a protruding portion protruding in the gap, being located more closely to the bottom portion side than the distal portion, and being joined to the corner portion of the leg portion.

According to an embodiment of the present disclosure, a thermionic cathode includes: a cathode body having an outer surface, and a sealing layer including one or more graphene sheets on the outer surface of the cathode body. According to another embodiment of the present disclosure, a method for manufacturing a thermionic cathode includes: depositing a sealing layer including one or more graphene sheets on an outer surface of a cathode body.

At least one emitter formed of an electron emissive material is positioned on a cathode assembly and is readily and reliably connected to at least one mounting member of the cathode assembly. The connections between the at least one emitter and an emitter support structure are formed directly between the at least one emitter and the emitter support structure by utilizing the at one mounting member on the emitter support structure that are positioned adjacent the at least one emitter and heated to secure the at least one emitter to the emitter support structure by welding the at least one mounting member to the at least one emitter and emitter support structure.

Thermionic cathodes and an electron emission apparatus are provided. The thermionic cathodes comprise perovskite material in crystal or sintered form. The thermionic cathodes provide strong electron emission at low operating temperatures.

Disclosed embodiments include cathodes with conformal cathode surfaces, vacuum electronic devices with cathodes with conformal cathode surfaces, and methods of manufacturing the same. In a non-limiting embodiment, a cathode for a vacuum electronic device includes: a substrate having a predetermined shape; and electron emissive material disposed on at least one portion of at least one surface of the substrate, a shape of the electron emissive material conforming to the predetermined shape of the substrate.