To improve the extraction efficiency of InGaN/GaN multiple quantum well light-emitting diodes (LEDs), nanosize cavities were fabricated on a top p-GaN surface by inductively coupled plasma etching utilizing self-assembled platinum clusters as an etch mask. The relative output power was increased up to 88% compared to that of the LED without nanosize cavities. This result could be attributed to an enhancement in the escape of light due to the angular randomization by the nanosize cavities and to the reduced contact resistance due to the increased contact area between the transparent metal layers and the p-GaN. (c) 2005 The Electrochemical Society.