Enhanced Light Extraction from Nanoporous Surfaces of InGaN/GaN-Based Light Emitting Diodes

Abstract

The authors fabricated anodic alumina by a two-step anodization process for samples of an Al foil template and an Al deposited film in order to form nanopores on the p-GaN surfaces of InGaN/GaN multi-quantum-well (MQW) light-emitting diodes (LEDs). The GaN nanopores formed by nanopatterning with the alumina template in an inductively coupled plasma dry etching process shows enhanced light extraction at a wavelength of 450 nm. The nanoporous alumina anodized from the deposited Al layer has a channel to allow the flow of electrolytes into the GaN surface and results in the surface etching effect showing light enhancement at 474 nm. The significant enhancement of light extraction has been correlated with the nanoscaled roughness of a randomly distributed and nanoporous p-GaN surface.