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.

What is claimed is:  
     
       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 which is formed at least in part as a carbon nano - cylinder, wherein the carbon nano - cylinder serves as a coating over a cathode tip structure.   
     
     
       11. A field emission cathode comprising: 
       
         a substrate;  
       
       
         a conducting material deposited over the substrate; and  
       
         a carbon nano - cylinder deposited over the conducting material.   
     
     
       12. The field emission cathode of  claim 11 , wherein the carbon nano- cylinder comprises a single - walled carbon nano - cylinder.   
     
     
       13. The field emission cathode of  claim 11 , wherein the carbon nano- cylinder comprises a multi - walled carbon nano - cylinder.   
     
     
       14. The field emission cathode of  claim 11 , wherein the carbon nano- cylinder at its end cap is open.   
     
     
       15. The field emission cathode of  claim 11 , wherein the conducting material is in a form of a cone. 
     
     
       16. The field emission cathode of  claim 11 , further comprising: 
       
         a catalyst material deposited on the conducting material.