A cathode structure for cold field electron emission and method of fabricating a single-tip cathode structure for cold field electron emission. The cathode structure comprises a pointed cathode wire; and a graphene-based coating on at least a tip of the pointed cathode wire. In a preferred embodiment, graphene is coated on nickel tips by chemical vapour deposition wherein nickel functions as a catalyst for growth of graphene. The cathode structure provides stable cold field emission for electron microscopy and lithography applications and exhibits an ultralow work function value of about 1.1 eV.

Electron emitters and method 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.

An electrical device comprising a substrate of diamond material and elongate metal protrusions extending into respective recesses in the substrate. Doped semiconductor layers, arranged between respective protrusions and the substrate, behave as n type semiconducting material on application of an electric field, between the protrusions and the substrate, suitable to cause a regions of positive space charge within the semiconductor layers.

A carbon nanotube field emitter comprises at least two electrodes and at least one graphitized carbon nanotube structure. The at least one graphitized carbon nanotube structure comprises a first end and a field emission end. The first end is opposite to the field emission end. The first end is fixed between the at least two electrodes, and the field emission end is exposed from the at least two electrodes and configured to emit electrons.

A vertical vacuum transistor with a sharp tip structure, and associated fabrication process, is provided that is compatible with current vertical CMOS fabrication processing. The resulting vertical vacuum channel transistor advantageously provides improved operational characteristics including a higher operating frequency, a higher power output, and a higher operating temperature while at the same time providing a higher density of vertical transistor devices during the manufacturing process.

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.

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 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.

A method for fabricating an electron field emission cathode, the field emission cathode including a substrate having a field emission layer engaged therewith, where the field emission layer incorporates a carbon nanotube and metal composite film to improve adhesion between the material and the substrate and to improve field emission characteristics of the cathode and field emission cathode devices implementing such cathodes.

A method for fabricating an electron field emission cathode, the field emission cathode including a substrate having a field emission layer engaged therewith, where the field emission layer incorporates modified carbon nanotubes and a matrix material to improve field emission characteristics of the cathode and field emission cathode devices implementing such cathodes.

The present disclosure provides a method of regenerating an electron source, the electron source including at least one emission site fixed on a needle tip, and the emission site including a reaction product formed by metal atoms and gas molecules. The method includes regenerating the electron source in situ if an emission capability of the electron source satisfies a regeneration condition.