Question

In terms of charge carriers, bias voltages, and depletion regions, exactly how does an LED work? How is light emitted in the process?

Answer 1

LEDs are p-n junction devices. The junction in an LED is forward biased (Forward bias = Forward biasing the p-n junction drives holes to the junction from the p-type material and electrons to the junction from the n-typematerial. At the junction the electrons and holes combine so that a continuous current can be maintained.) and when electrons cross the junction from the n- to the p-type material it makes a depletion region so that the current flow can be continuous, the electron-hole recombination process produces some photons in the IR or visible in a process called electroluminescence. An exposed semiconductor surface can then emit light. The applied voltage should be greater than the biased voltage.