A light-emitting transistor or LET is a form of transistor that emits light. Higher efficiency than light-emitting diode (LED) is possible.

Light-emitting transistor (LET)
Working principleElectroluminescence
InventedMilton Feng Nick Holonyak


Reported in the January 5, 2004 issue of the journal Applied Physics Letters, Milton Feng and Nick Holonyak,[1] the inventor of the first practical light-emitting diode (LED) and the first semiconductor laser to operate in the visible spectrum, made the world's first light-emitting transistor. This hybrid device, fabricated by Feng's graduate student Walid Hafez, had one electrical input and two outputs (electrical output and optical output) and operated at a frequency of 1 MHz. The device was made of indium gallium phosphide, indium gallium arsenide, and gallium arsenide, and emitted infrared photons from the base layer.[2][3]

See also


  1. ^ Feng, M.; Holonyak, N.; Hafez, W. (2004). "Light-emitting transistor: Light emission from InGaP/GaAs heterojunction bipolar transistors". Applied Physics Letters. 84 (1): 151–153. Bibcode:2004ApPhL..84..151F. doi:10.1063/1.1637950.
  2. ^ "First Light-Emitting Transistor". IEEE Spectrum.
  3. ^ New light-emitting transistor could revolutionize electronics industry