Periodic indentation patterns fabricated on AlGaInP light emitting diodes and their effects on light extraction

We report a novel method for fabricating periodic indentation patterns on AlGaInP light emitting diodes (LEDs) that can effectively improve the light extraction efficiency. The patterns consist of hemispherical pits created by directly imprinting the top GaP window layer of AlGaInP LEDs with patterned sapphire (PS). The angle resolved electroluminescence tests reveal that the patterned chips show an average light emission enhancement of 155% over the original planar chips.