Ultra-high External Efficiency From Surface Textured Thin-film LEDs

Dire need for high external quantum efficiency (η_(ext)) visible light-emitting-diodes (LED's) is clearly seen as the flat panel display technology is rapidly evolves. However, there is an enormous gap between the theoretical efficiency of LED's and their actual efficiency. It has been known that good quality III-V double heterostructures can have over 90% internal quantum yields (η) for direct band-gap compounds and over 99% for AlGaAs/GaAs/AlGaAs, as we have demonstrated recently. On the other hand, run-of-the-mill commercial LED's are usually only a few percent efficient (externally).