Transport equation model for the optics of light-emitting diodes with arbitrary surface microstructure

Abstract

We present a transport equation model for the light emission and transport in light-emitting diodes. Using the model, we compare the brightness and quantum efficiency of LEDs with light extraction through a smooth, light scattering or perfectly transparent planar surface. We show that surface roughened LEDs can perform almost ideally and that the thickness of the active region in LEDs has a large effect on the photon extraction and the overall efficiency.