Work Function of Diode
The work function of a diode material is the minimum amount of energy required to remove an electron from the surface of the metal or semiconductor used in the diode. It is a crucial parameter because it directly influences thermionic emission, which is the process by which electrons are emitted from a heated cathode in vacuum and thermionic diodes.
Richardson’s Law (also called the Richardson–Dushman equation) explains the relationship between the thermionic emission current density and temperature. According to this law, when the cathode of a diode is heated, electrons gain sufficient thermal energy to overcome the work function barrier and escape from the surface.
Features of Work Function of Diode – Richardson’s Law
- Explains thermionic emission of electrons from a heated cathode in a diode.
- Establishes a direct relationship between emission current density and temperature.
- Highlights the importance of work function (φ) in controlling electron emission.
- Demonstrates that lower work function materials give higher emission at lower temperatures.
- Uses an exponential relationship, accurately describing real emission behavior.
