Hierarchical Field Emission Devices - Hierarchical Nanostructures for Energy Devices - page 230

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CHAPTER 10
Hierarchical Field Emission
Devices

E. STRATAKIS

Institute of Electronic Structure and Laser, Foundation for Research &
Technology—Hellas, (IESL-FORTH), P.O. Box 1527, Heraklion 711 10,
Greece
Email: [e-mail]

10.1 Introduction to Field Electron Emission
Technology
Field-electron emission (FE) refers to the emission of electrons from a solid
cathode (generally in the shape of a sharp tip) into a vacuum under the
influence of a strong electric field of the order of 10 6 -10 7 Vcm 1 , otherwise
known as cold cathode electron emission. The pointed or conical shape of
the cathode strongly enhances the electric field at the tip, originating from
biasing the cathode negatively with respect to a nearby anode. FE is a form of
quantum mechanical tunneling which occurs when electrons pass through
the potential energy barrier at the interface between the cathode and the
vacuum. Field emitting cathodes can be integrated into small, lightweight
devices and can be operated at high repetition rates due to their rapid on/off
switching speed. Potential applications include vacuum microelectronic
devices, such as electron guns and microwave power amplifiers, electron
microscopy and FE electronic devices, such as flat panel FE displays (FEDs).
One of the first-studied applications of FE was developed in surface
science for the study of surface diffusion of adsorbates over clean metal

.