 ##  [Thermionic Emission](/thermionic-emission) 

  ##  [Thermionic Emission](https://engineering.quantumdictionary.io/thermionic-emission-0) 

  
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**Engineering &amp; Applied Technologies Dictionary**

 
Definition

The process by which electrons escape from a material surface when thermal energy enables a fraction of carriers to surmount the surface potential barrier (work function φ); significant in vacuum or low-pressure environments and strongly dependent on temperature and the material's effective work function and surface condition.