Carbon nanotube field emission array and method for fabricating the same

Abstract

A field emission array (FEA) using carbon nanotubes having characteristics of low work function, durability and thermal stability, and a method for fabricating the same are provided. The field emission array uses carbon nanotubes as electron emission sources, thereby lowering a work function and dropping driving voltage. Accordingly, a device can be driven at low voltage. In addition, resistance to gases, which are generated during the operation of a device, is improved, thereby increasing the life span of an emitter. The method prints a mixed paste using extrusion or screen printing and performs sintering, thereby fusing carbon nanotubes such that the carbon nanotubes are aligned in a single direction.

What is claimed is:  
     
         1 . A field emission array using carbon nanotubes, comprising: 
 front and rear substrates facing each other and separated by a predetermined distance;    anodes and cathodes formed on the front and rear substrates facing each other, respectively, in a striped pattern, the anodes and the cathodes crossing each other;    carbon nanotubes fixed on the cathodes corresponding to intersections between the cathodes and the anodes; and    a metal fuser element for fixing the carbon nanotubes on the cathodes and conducting currents between the cathodes and the carbon nanotubes.    
     
     
         2 . The field emission array of  claim 1 , further comprising: 
 an insulating layer deposited on the cathodes around the carbon nanotubes and the rear substrate; and    gates formed on the insulating layer in a striped pattern to be parallel to the anodes.    
     
     
         3 . The field emission array of  claim 1  or  2 , wherein each of the anodes is formed of an ITO film and coated with phosphor.  
     
     
         4 . A method of fabricating a field emission array using carbon nanotubes, the method comprising the steps of: 
 (a) forming cathodes on a rear substrate in a striped pattern;    (b) printing a mixture of carbon nanotubes, metal powder and organic binder on predetermined areas of the cathodes;    (c) vaporizing the organic binder by sintering the mixture and anchoring the carbon nanotubes on the cathodes by diffusing the metal powder; and    (d) combining a front substrate, on which anodes are formed in a striped pattern, with the rear substrate having the cathodes on which the carbon nanotubes are anchored.    
     
     
         5 . The method of  claim 4 , further comprising the steps of: 
 forming an insulating layer on the tops of the cathodes other than portions to which the carbon nanotubes are to be adhered and on the top of the exposed rear substrate, before the step (b); and    forming gates on the insulating layer after the step (c).    
     
     
         6 . The method of  claim 4  or  5 , wherein in the step (b), the metal powder is composed of metal particles having a diameter of 0.1-10 μm.  
     
     
         7 . The method of  claim 4  or  5 , wherein in the step (b), the metal powder is diffused at a temperature of 250-500° C.  
     
     
         8 . The method of  claim 7 , wherein the metal powder is composed of particles of a metal selected from the group consisting of Ag, Al, Ni, Cu and Zn.  
     
     
         9 . The method of  claim 4  or  5 , wherein in the step (b), the metal powder is melted at a low temperature of 100-350° C., and in the step (c), the mixture is sintered to evaporate the organic binder, and the low melting point metal powder is melted to anchor the carbon nanotubes on the cathodes.  
     
     
         10 . The method of  claim 9 , wherein the metal powder is composed of particles of a metal selected from the group consisting of Pb, In, InSn, PbSn, AuSn and a metal alloy thereof, and the diameter of each of the particles is 0.1-10 μm.  
     
     
         11 . The method of  claim 4  or  5 , wherein in the step (b), the organic binder is composed of at least one selected from the group consisting of α-terpineol, ethyl cellulose and butyl carbitol acetate.  
     
     
         12 . The method of  claim 4  or  5 , wherein in the step (b), the printing is performed by an extrusion method using a filter for aligning the carbon nanotubes.  
     
     
         13 . The method of  claim 4  or  5 , wherein in the step (b), the printing is performed by a screen printing method using a metal mesh screen which is patterned for aligning the carbon nanotubes.  
     
     
         14 . The method of  claim 4  or  5 , wherein in the step (c), the sintering is performed at a temperature of 200-500° C.