Graphene-based field emission cold cathode and preparation method

Abstract

The invention belongs to the field of crossing of a vacuum electronics technology and a novel carbon material technology and particularly relates to a graphene-based field emission cold cathode and apreparation method. The field emission cold cathode comprises a substrate and an emitter, wherein the substrate is taken as a conductive substrate and is a silicon wafer or a metal sheet; the emitteris a graphene film layer; the graphene film layer is in close contact with the substrate; the thickness of the graphene film layer is 20-180 microns; and the graphene film layer is formed by grapheneclusters of which the particle sizes are 15-45 microns. The graphene-based cold cathode provided by the invention can be prepared by using the method, is in an array form, has good performance advantages of a low starting electric field, a low threshold electric field and high emission current, and can be applied to the fields, such as field emission display (FED) as an excellent electronic source.

Description

technical field [0001] The invention belongs to the intersecting field of vacuum electron technology and novel carbon material technology, and specifically relates to a graphene-based field emission cold cathode and a preparation method thereof. Background technique [0002] By applying an external electric field, the height of the barrier on the surface of the material is reduced, the width is reduced, and electrons tunnel through the barrier to escape from the surface of the material, which is field electron emission. A cathode capable of field electron emission is called a field emission cold cathode, and the field emission cold cathode can emit electrons at a relatively low external electric field without providing additional energy from the outside. As an electron source with low energy consumption, excellent performance, and stable operation, field emission cold cathodes have been used in scanning electron microscopes, microwave tubes, X-ray tubes and other fields, esp...

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Problems solved by technology

The microwave plasma chemical vapor deposition method has high cost and poor controllability, and it is difficult to achieve large-area and uniform growth of graphene films; the screen printing method can achieve large-area preparation of graphene films with high uniformity, but due to the graphene layer The over-dense shielding effect is prominent, which reduces the field emission performance; the electrophoretic deposition method is easy to implement, but as the deposition progresses, the uniformity of the film and the contact tightness between the sheets are affected; the coating method is simple and easy to implement, and can Realize large-area and uniform preparation of graphene film, but due to graphene agglomeration and excessive distribution, the emission current density is low

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