Drooping as a simple characterization tool for extraction efficiency and optical losses in light emitting diodes

We extend the previous droop models developed for InGaN light emitting diodes (LEDs) by accounting for the light extraction and show that drooping can be used to quantify both the extraction efficiency and the optical losses in LEDs. Our model allows very simple characterization of LEDs by an integrating sphere and therefore provides an attractive characterization tool to measure the most important loss parameters of various LED structures. In particular, the approach allows evaluation of the effects of various optical losses and photon recycling on the efficiency and consequently allows more efficient optimization of the LED structures. As an additional benefit, our measurement method does not necessarily require any fitting of the data. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3494085]