Light Extraction Improvement From GaN-Based Light-Emitting Diodes With Nano-Patterned Surface Using Anodic Aluminum Oxide Template
An improvement of light extraction from GaN-based light-emitting diodes (LEDs) was demonstrated by forming surface nano-structures using an anodic aluminum oxide (AAO) template as a dry etching mask. Nano-pores were simultaneously formed on indium tin oxide and GaN surfaces of LED with different pore depths by the same procedural steps, with a pore density and pore diameter of 1.1t109/cm2 and 163 plusmn 31 nm, respectively. The nano-patterned LEDs achieved a top-face light output power enhancemetop-face light output power enhancementnt of 72% compared to the conventional LEDs at 20 mA. The light extraction effects of the nano-structures on the trapped optical modes in LED were revealed by scanning electron microscopy and microscopic electroluminescence.