Field emission cathode

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.

What is claimed:  
     
       1. A field emission cathode which consists of an electrically conducting material having the shape of a narrow rod or a knife edge to achieve high magnification of the electric field strength, such that the electron-emitting part of the field emission cathode has cylindrical molecules formed at least in part as single-shell or multiple-shell carbon nano-cylinders. 
     
     
       2. The device of  claim 1 , wherein the carbon nano-cylinders have end caps. 
     
     
       3. The device of  claim 1 , wherein the single- or multiple-shell carbon nano-cylinders are collected into bundles. 
     
     
       4. The device of  claim 1 , wherein the carbon nano-cylinders are filled with metal. 
     
     
       5. The device of  claim 1 , wherein the carbon nano-cylinders at least partly have endohedral or exohedral compounds with other atoms or molecules. 
     
     
       6. The device of  claim 1 , wherein the field emission cathode forms the tip of a field electron microscope, a field ion microscope, a scanning tunnel microscope, or a scanning power microscope. 
     
     
       7. The device of  claim 1 , wherein a plurality of similar field emission cathodes is disposed in a line or a plane, and thereby forms a linear or planar electron source. 
     
     
       8. The device of  claim 1 , wherein a plurality of similar field emission cathodes is disposed in a plane in the form of a matrix, and the field emission cathodes can be driven individually, and the field emission cathodes represent the electron sources for the image points of a visual display system. 
     
     
       9. The device of  claim 8 , wherein the plurality of similar field emission cathodes is in the range of 10,000 to 100,000 molecules. 
     
     
       10. A field emission cathode comprising an electron- emitting part of the cathode formed at least in part as a carbon nano - cylinder.    
     
     
       11. The field emission cathode of  claim 10 , wherein the carbon nano- cylinder is single - walled.    
     
     
       12. The field emission cathode of  claim 10 , wherein the carbon nano- cylinder has an end cap.    
     
     
       13. The field emission cathode of  claim 10 , wherein the carbon nano- cylinder is filled with metal.    
     
     
       14. The field emission cathode of  claim 10 , wherein the carbon nano- cylinder is multi - walled.    
     
     
       15. A field emission apparatus comprising: 
       
         a substrate;  
       
       
         a carbon nanotube deposited over the substrate; and  
       
       
         an electrode operable for creating an electric field in order to promote an emission of electrons from the carbon nanotube.  
       
     
     
       16. The field emission apparatus of  claim 15 , wherein the electrode includes a gate electrode positioned a first distance from said substrate.  
     
     
       17. The field emission apparatus of  claim 15 , wherein the electrode includes a conducting material deposited over the substrate.  
     
     
       18. The field emission apparatus of  claim 15 , wherein the carbon nanotube comprises a single- walled carbon nanotube.    
     
     
       19. The field emission cathode of  claim 15 , wherein the carbon nanotube comprises a multi- walled carbon nano - cylinder.    
     
     
       20. The field emission cathode of  claim 15 , wherein the carbon nanotube comprises a carbon nanotube having two walls.  
     
     
       21. The field emission apparatus of  claim 15 , further comprising an anode positioned a distance from the substrate.  
     
     
       22. The field emission cathode of  claim 15 , wherein the electrode includes a conducting material deposited over the substrate.  
     
     
       23. A field emission apparatus, comprising: 
       
         a substrate; and  
       
         one or more electron emitter structures comprising a carbon nano - cylinder deposited on a growth surface over the substrate, wherein the carbon nano - cylinder is grown catalytically in situ on the growth surface from a carbon - containing precursor material.