Light-Emitting Diode (LED)

Forward-biased direct-bandgap pn. Recombining electrons release photons of energy E_g; the wavelength is set by the material.

N_A (cm⁻³)

N_D (cm⁻³)

V_forward (V)

Temperature (K)

Indirect-bandgap materials (Si, Ge) make poor LEDs. Direct bandgap (GaAs, InP, GaN) is required for efficient photon emission.

E_c E_v Photons ↑

✍ Derivation — click to expand ▶