LU501211B1 - Novel metal- based carbon nanotube field emission cold cathode - Google Patents

Abstract

The present disclosure discloses a novel carbon nanotube field emission cold cathode, which includes a metal substrate whose surface is configured with a stereo microstructure array, on which there is arranged a carbon nanotube film layer. The novel carbon nanotube field emission cold cathode of the present invention can realize better current emission capability and emission stability than the existing carbon nanotube field emission cold cathode.

Description

DESCRIPTION LUS01217 NOVEL METAL- BASED CARBON NANOTUBE FIELD EMISSION COLD

CATHODE Technical Field The present disclosure relates to a carbon nanotube field emission cold cathode in the cross field of the vacuum electronic technique and the new material technique, and more particularly relates to a novel carbon nanotube field emission cold cathode.

Background The field emission is a phenomenon in which solids emit electrons under strong electric field and is essentially different from electron emissions in other forms. For thermal electron emission, optical electron emission and secondary electron emission, etc., internal electrons within solids obtain thermal energy, photon energy and initial electron energy, and are excited to the energy state higher than the surface barrier and escaped from solid surfaces. For the field emission, electrons penetrate the barrier under the action of strong electric field to escape, which means it can achieve an emission current density several orders of magnitude higher than electron emissions in other forms and shows excellent application prospects in aspects such as field emission display, high power microwave technology, strong-current electron beam source and novel sensors. Therefore, the field emission cold cathode has always been highly valued by each country. Especially as strong-current electron beam source can be widely used in fields such as strong-current accelerator, high power microwave and electron beam irradiation, it shows important application prospects in scientific areas such as physics, chemistry, information, material, life, biology, medicine and national defense.

During the development of the field emission technology, the improvement of current emission capability and the improvement of emission reliability and stability have always been two important aspects thereof. Therefore, the field emission cold cathode has become a hot spot research area in recent years due to its electron emission ability much higher than conventional cathode. The researchers continue to seek ways to improve the cold cathode emission performance, for which reason the cold cathode has also evolved from the cone LUS01217 array type field cold cathode proposed by C. A. Spindt in 1968 to the current film cold cathode adopting film materials such as carbon nanotubes and diamonds as the emitter. Such cathodes typically have excellent field emission properties and its emission current is large especially due to the large quantity number of the carbon nanotube tips, and thus the. However, when the carbon nanotube density is too large, the shielding effect will occur, thereby limiting the tendency that the emission current increases along with the density of carbon nanotubes. Further, the growth substrate of the conventional carbon nanotube film is usually semiconductor silicon. When the emission current of the carbon nanotube film is too large, the contact resistance between carbon nanotubes and the substrate will produce huge jeopatics under large current, causing damages to the emission tip of carbon nanotubes and resulting in failure or damage to the field emission cathode.

In order to solve the above problems, we once introduced stereo microstructures and metal buffer layers on the silicon substrate on which carbon nanotube film grows, so to increase the emission area per unit cathode plane and reduce the current shielding effect, thereby realizing the improvement of current emission capability, reducing the contact resistance between the carbon nanotube and the conductive substrate by using the metal buffer layer, lowering the thermal effect upon the time of high current emission, increasing the emission stability of the cathode.

However, metal materials are significantly better than semiconductor materials in terms of current transmission capacity and thermal performance. Accordingly, the present disclosure proposes a carbon nanotube film cold cathode grown on a metal substrate with a stereo microstructure to achieve better current emission capability and emission stability.

Summary of the Invention It is an object of the present disclosure to provide a novel carbon nanotube field emission cold cathode, which can achieve better current emission capability and emission stability than the existing carbon nanotube field emission cold cathode.

The present disclosure adopts the following technical solution: a novel carbon nanotube LUS01217 field emission cold cathode comprising a metal substrate whose surface is configured with a stereo microstructure array, on which there is arranged a carbon nanotube film layer.

The stereo microstructure of the metal substrate is also configured with graphene transition layer and the carbon nanotube film layer is configured on the graphene transition layer.

The metal substrate is a copper substrate or a stainless steel substrate.

The stereo microstructure array 1s a conical microstructure array.

The present disclosure provides a novel carbon nanotube field emission cold cathode, which can realize better current emission capability and emission stability than the existing carbon nanotube field emission cold cathode; wherein the stereoscopic structure on the metal surface can effectively improve the electron emission of the cathode, thereby improving the current emission capability of the carbon nanotube cold cathode; the metal substrate and the graphene transition layer have good thermal conductivity and electrical conductivity, which can reduce the contact resistance between the carbon nanotube and the substrate, thereby improving the emission stability.

Brief Description of Drawings FIG. 1 is a structural diagram of the carbon nanotube field cold cathode n the present disclosure; FIG. 2 is a stereo structural diagram of Figure 1; FIG. 3 is a structural diagram of the carbon nanotube emission cold cathode with a graphene transition layer in the present disclosure.

Detailed Description of Preferred Embodiments As shown in FIG. 1 and FIG. 2, the present disclosure provides a novel carbon nanotube field emission cold cathode comprising a metal substrate 1 whose surface is configured with a stereo microstructure array 2, on which there is arranged a carbon nanotube film 3; the stereo microstructure array 2 is a conical microstructure array or other microstructure array, wherein the stereo microstructure is used to enhance the electric field strength near the substrate LUS01217 surface and suppress the electric field shield to improve the current emission capability of the cathode. The metal substrate 1 is a copper substrate or a stainless steel substrate, and it may also be other metal substrate or alloy substrates to reduce the contact resistance between the carbon nanotube and conductive substrate by using a metal substrate and reduce the thermal effect upon the time of high current emission, thereby improving the emission stability of the cathode. The geometric scale for the bottom side of the conical microstructure is set as a, and the spacing between two adjacent sides of the two cone microstructure is set as b, wherein the sizes of a and b are determined according to the actual needs, (for example, a is 1-100 microns, b is 0-100 microns) and the material of the tapered microstructure is the same as the metal substrate.

As shown in FIG. 3, further, there is a grapheme transition layer 4 on the stereo microstructure 2 of the metal substrate 1, and the carbon nanotube film layer 3 is configured on the graphene transition layer 4.

Claims (4)

CLAIMS LU501211

1. A novel carbon nanotube field emission cold cathode, comprising: a metal substrate whose surface is configured with a stereo microstructure array, on which there is arranged a carbon nanotube film layer.

2. The novel carbon nanotube field emission cold cathode according to claim 1, wherein the stereo microstructure of the metal substrate is also configured with graphene transition layer and the carbon nanotube film layer is configured on the graphene transition layer.

3. The novel carbon nanotube field emission cold cathode according to claim 1, wherein the metal substrate is a copper substrate or a stainless steel substrate.

4. The novel carbon nanotube field emission cold cathode according to claim 1, wherein the stereo microstructure array is a conical microstructure array.