The present application discloses an array substrate comprising a first substrate, a first electrode on the first substrate, a passivation layer on a side of the first electrode distal to the first substrate, the passivation layer comprising a plurality of first vias, each of which corresponds to a different part of the first electrode, an electron emission source layer on a side of the first electrode distal to the first substrate comprising at least one electron emission source in each of the plurality of first vias, and a dielectric layer on a side of the first electrode distal to the first substrate comprising a plurality of dielectric blocks corresponding to the plurality of first vias, at least a portion of each of the plurality of dielectric blocks in each of the plurality of first vias. The at least one electron emission source comprises a first portion having a first end and a second portion having a second end. The first end is in contact with the first electrode, the first portion is within a corresponding one of the plurality of dielectric blocks. The second portion and the second end are outside the corresponding one of the plurality of dielectric blocks.

A horizontal multilayer junction-edge field emitter includes a plurality of vertically-stacked multilayer structures separated by isolation layers. Each multilayer structure is configured to produce a 2-dimensional electron gas at a junction between two layers within the structure. The emitter also includes an exposed surface intersecting the 2-dimensional electron gas of each of the plurality of vertically-stacked multilayer structures to form a plurality of effectively one-dimensional horizontal line sources of electron emission.

The emitter of the present invention includes a nanowire. The nanowire is formed from a hafnium carbide (HfC) single crystal, and at least an end portion of the hafnium carbide single crystal, from which electrons are to be emitted, is covered with hafnium oxide (HfO.sub.2). In the emitter, the thickness of the hafnium oxide may be 1 nm to 20 nm.

An emitter containing a metal boride material has an at least partly rounded tip with a radius of 1 m or less. An electric field can be applied to the emitter and an electron beam is generated from the emitter. To form the emitter, material is removed from a single crystal rod to form an emitter containing a metal boride material having a rounded tip with a radius of 1 m or less.

The present application discloses an array substrate comprising a first substrate, a first electrode on the first substrate, a passivation layer on a side of the first electrode distal to the first substrate, the passivation layer comprising a plurality of first vias, each of which corresponds to a different part of the first electrode, an electron emission source layer on a side of the first electrode distal to the first substrate comprising at least one electron emission source in each of the plurality of first vias, and a dielectric layer on a side of the first electrode distal to the first substrate comprising a plurality of dielectric blocks corresponding to the plurality of first vias, at least a portion of each of the plurality of dielectric blocks in each of the plurality of first vias. The at least one electron emission source comprises a first portion having a first end and a second portion having a second end. The first end is in contact with the first electrode, the first portion is within a corresponding one of the plurality of dielectric blocks. The second portion and the second end are outside the corresponding one of the plurality of dielectric blocks.

A horizontal multilayer junction-edge field emitter includes a plurality of vertically-stacked multilayer structures separated by isolation layers. Each multilayer structure is configured to produce a 2-dimensional electron gas at a junction between two layers within the structure. The emitter also includes an exposed surface intersecting the 2-dimensional electron gas of each of the plurality of vertically-stacked multilayer structures to form a plurality of effectively one-dimensional horizontal line sources of electron emission.

Some embodiments of vacuum electronics call for nanoscale field-enhancing geometries. Methods and apparatus for using nanoparticles to fabricate nanoscale field-enhancing geometries are described herein. Other embodiments of vacuum electronics call for methods of controlling spacing between a control grid and an electrode on a nano- or micron-scale, and such methods are described herein.

A horizontal multilayer junction-edge field emitter includes a plurality of vertically-stacked multilayer structures separated by isolation layers. Each multilayer structure is configured to produce a 2-dimensional electron gas at a junction between two layers within the structure. The emitter also includes an exposed surface intersecting the 2-dimensional electron gas of each of the plurality of vertically-stacked multilayer structures to form a plurality of effectively one-dimensional horizontal line sources of electron emission.

The present application discloses an array substrate comprising a first substrate, a first electrode on the first substrate, a passivation layer on a side of the first electrode distal to the first substrate, the passivation layer comprising a plurality of first vias, each of which corresponds to a different part of the first electrode, an electron emission source layer on a side of the first electrode distal to the first substrate comprising at least one electron emission source in each of the plurality of first vias, and a dielectric layer on a side of the first electrode distal to the first substrate comprising a plurality of dielectric blocks corresponding to the plurality of first vias, at least a portion of each of the plurality of dielectric blocks in each of the plurality of first vias. The at least one electron emission source comprises a first portion having a first end and a second portion having a second end. The first end is in contact with the first electrode, the first portion is within a corresponding one of the plurality of dielectric blocks. The second portion and the second end are outside the corresponding one of the plurality of dielectric blocks.

Some embodiments of vacuum electronics call for nanoscale field-enhancing geometries. Methods and apparatus for using nanoparticles to fabricate nanoscale field-enhancing geometries are described herein. Other embodiments of vacuum electronics call for methods of controlling spacing between a control grid and an electrode on a nano- or micron-scale, and such methods are described herein.