LED Light-emitting Principle

DeRun   Views:4431    05/19-2013

The substantive structure of the LED is a semiconductor PN junction, the core part is composed by a P-type semiconductor and the N-type semiconductor wafer, a transition layer, called the PN junction between the P-type semiconductor and the N-type semiconductor. Its light-emitting principle can be used to do explain the energy band structure of the PN junction.

Semiconductor materials for fabricating a semiconductor light-emitting diode is heavily doped N region has a lot of high electron mobility in thermal equilibrium, P area more low hole mobility.

Limit in the normal state and the PN junction blocking layer, the not both nature composite, while when the forward voltage to a PN junction to be opposite to the direction of the electric field due to the applied electric field direction and the barrier region self, and therefore the barrier height reduced, the electrical injection barrier width narrows destroy the dynamic balance of the PN junction, generated minority carriers [16].

Hole injection from P N area, the same injection of electrons from the N area to P area, the injected minority carriers composite majority carriers in the same area, the excess energy in the form of light radiated.

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