Field emission cathode having an electrically conducting material shaped of a narrow rod or knife edge

Abstract

A field emission cathode device consisting of an electrically conducting material and with a narrow, rod-shaped geometry or a knife edge, to achieve a high amplification of the electric field strength is characterized in that the electron-emitting part of the field emission cathode at least partly has preferred cylindrical host molecules and / or compounds with host compounds and / or cylindrical atomic networks, possibly with end caps with diameters measuring in the nanometer range.

Description

The invention relates to a field emission cathode device of an electrically conducting material and with a narrow, rod-shaped geometry or a knife edge to achieve high amplification of the electric field strength, such that the electron-emitting part of the field emission cathode has cylindrical molecules. The invention also relates to a method for producing such a field emission cathode device.Field emission means the emission of electrons from the surface of an electric conductor under the action of an electric field exceeding 10.sub.9 V / m. In practice, such field strengths are realized at sharp edges or tips, where the field strength is amplified. High vacuum is necessary to avoid gas discharges.DESCRIPTION OF THE PRIOR ARTField emission cathodes are used, for example, in field electron microscopes, in electron accelerators, in high-power switches (OS DE 39 24 745 A1) and in field emission diodes and field emitter arrays for vacuum microelectronics (thus for example Busta, Vacuum ...

AI Technical Summary

Benefits of technology

The present invention is based on the object or on the technical problem of specifying a field emission cathode which avoids the disadvantages of the prior art, assures high emission quality, makes possible a longer lifetime, and in particular resists bombardment with residual gas ions. Furthermore, the present invention is based on the object or on the technical problem of specifying a method for producing a field emission cathode of the type mentioned in the introduction, so as to assure technically optimal manufacture together with economy.

Using well-known carbon nano-cylinders as a field emission cathode thus combines the advantage of optimal geometry with high strength, thus assuring that the emission properties of such field emission cathodes will not change during their operation, in contrast to previously used cathode tips.

Problems solved by technology

A disadvantage in the use of tips and edges, which have been produced by the known methods, is that the electron stream declines with operating time, since the tips or edges are destroyed by the positive ions of the unavoidable residual gas in the system.

Furthermore, field emission cathodes for vacuum microelectronics cannot be produced in their optimal geometry by the prior art.

However, this method is impractical, and in particular is not suited for field electron arrays with many cathode tips, as is desired in vacuum microelectronics.

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