Internal quantum efficiency of high-brightness AlGaInP light-emitting devices

The internal quantum efficiency of ( Al x Ga 1 − x ) 0.5 In 0.5 P light-emitting devices (LEDs), with an emission wavelength ranging from 650 to 560 nm, is determined by means of a model that takes into account the radiative and nonradiative recombination in the active layer, the diffusive leakage of carriers into the confining layers, and the influence of photon recycling on the light extraction efficiency. The evaluation is based on measurements of the external quantum efficiency of the LEDs as a function of the operating current and temperature. The analysis provides the wavelength dependence of both the nonradiative recombination as well as the carrier leakage.