Increasing the extraction efficiency of blue lignt emitting diodes via laser patterned Ga-polar p-GaN surface

We report here the laser patterned Ga-polar p-GaN surface to improve the light extraction efficiency of GaN based blue light emitting diodes (LEDs) by using a pulsed UV laser in combination with a mirror scanner. The patterns created on p-GaN are confirmed to be suitable for light extraction and a 34.9% enhancement of the electroluminescent (EL) emission intensity has been obtained. Detailed discussions on the effects of laser on LEDs and the angular dependence of the emission profile are also provided. This method could be extended to other III-V LEDs and LEDs on SiC for fabricating highly efficient LEDs. [GRAPHICS] The schematic of laser fabrication equipment, SEM image of patterned p-GaN surface and guided-modes extraction photograph of patterned GaN epilayer. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim