Enhanced light extraction of GaN-based light emitting diodes via simultaneous ITO texturing and n-GaN nanorod formation using Al2O3 powder

Abstract

The authors have fabricated the surface-textured GaN based light emitting diodes (LEDs) by incorporating a transparent powder onto an indium tin oxide (ITO) surface and exposed n-GaN surface to improve the light extraction efficiency by decreasing the total internal reflection and by achieving an angular randomization of the photons. The ITO surface and exposed n-GaN surface was simultaneously textured using a method known as natural lithography. The Al2O3 powders were coated onto the LED surface as a random mask for dry etching. After packaging, the light output powers of the LEDs with the textured ITO layer and with nanorods at n-GaN were enhanced about ∼ 11 and 15 %, respectively, compared with that of the conventional LED. Also, the light output power of the LED with both the textured ITO layer and the formed n-GaN nanorods increased by ∼ 24% compared with that of the conventional LED.