On relationship between the field at an autoemitter top, anode voltage and cathode geometry

• Published in: Solid-state electronics Vol. 56; no. 1; pp. 35 - 39
• Main Authors: Stetsenko, B.V., Shchurenko, A.I.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2011; Elsevier
• Subjects: Anode; Anodes; Applied sciences; Autoemission; Cathode; Cathodes; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Curvature; Diodes; Electric fields; Electric potential; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Exact sciences and technology; Field; Law; Materials science; Mathematical analysis; Mathematical models; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Physics; Potential; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Surface double layers, schottky barriers, and work functions; Tip; Voltage; Field; Tip; Potential; Anode; Cathode; Autoemission; Electric potential; Potential barrier; Diode; Uniform field; Transmitter; Carbon nanotubes; Modeling; Solid state; Radius of curvature; Work function; Electric field; Electron emission; Transparent material; Fowler Nordheim tunneling
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2010.11.006

► At a cathode size lowring an emission current become less of Fowler-Nordheim it. ► A field emission is appear when a voltage along cathode is large work function. ► Under the action of contact potetial a nanocathode field emission are observed. Currently a lot of electron emission experiments both in carbon nanotubes with top curvature radius <1nm, and in emitters as short as 103nm with top curvature radius of some tens nanometer are carried out. Experimental results can be explained by a tunnel emission through potential barrier in vacuum near the solid-state cathode border making use of Fowler–Nordheim law. However, in case of cathodes with radius of top curvature less than 100nm this law is not valid. To proof this statement, the potential of an autoemission diode consisting of a tip cathode located on a flat metal base and flat anode, its dependence on the shape, height of the tip as well as voltage drop on it were calculated in this paper. It has been shown that with cathode tip height and its radius of curvature decreasing (⩽100nm) the transparency of the potential barrier depends non-linearly on the anode voltage in the Fowler–Nordheim coordinates when the cathode tip height decreases from 1000 down to 150nm. To obtain a measurable autoemission current, work function must not exceed the uniform field’s potential drop between cathode top and its base. Deduced is the analytic formula for the electric field potential that extends approximation features for real cathodes shapes and enables more accurate electric field modeling at the surface.