J B Gunn discovered periodic fluctuations of current passing through the n-type GaAs specimen when the applied voltage exceeded a certain critical value. In these diodes, there are two valleys, L & U valleys in conduction band and the electron transfer occurs between them, depending upon the applied electric field. This effect of population inversion from lower L-valley to upper U-valley is called Transfer Electron Effect and hence these are called as Transfer Electron Devices (TEDs).

Applications of Gunn Diodes

Gunn diodes are extensively used in the following devices −

• Radar transmitters
• Transponders in air traffic control
• Industrial telemetry systems
• Power oscillators
• Logic circuits
• Broadband linear amplifier