Light-output enhancement of GaN-based light-emitting diodes by using hole-patterned transparent indium tin oxide electrodes

We have demonstrated the improvement of the light-output power of GaN-based light-emitting diodes (LEDs) using hole-patterned indium tin oxide (ITO) p-type electrodes. Hole patterns were defined by a laser holographic lithography combined with a postlithography deposition process. It is shown that near-UV LEDs made with the patterned ITO with a hole period of 710nm and a size of 320nm give 23% and 67% higher light-output power (at 20mA) than those of LEDs with unpatterned ITO and Ni∕Au contacts, respectively. It is further shown that the reduction of the hole period results in an additional improvement of light-output power.