InGaN Light-Emitting Diodes with Multiple-Porous GaN Structures Fabricated through a Photoelectrochemical Etching Process

摘要

Multiple-porous GaN structures were formed in InGaN light-emitting diodes (LEDs) structures through a selective photoelectrochemical (PEC) etching process. A 1.3 μm-thick PEC-treated n~+ -GaN:Si layer consisting of nanoporous, whisker, fiber-shaped, networking, and air-gap structures located at the bottom of the LED structure was fabricated. Multiple-porous GaN structures were formed caused by the non-uniformly lateral etching rate on the n~+ -GaN:Si layer under a high PEC-biased voltage. An 80 μm lateral etching width and a 70% bottom roughened area ratio were measured on the treated LED structure without affecting the electrical properties. The light output power of the treated LED had an approximate enhancement of 57% compared with the non-treated LED structure. Fabry-Perot interferences of the treated LED structures were observed in angle-resolved electroluminescence spectra indicating that the effective optical refractive index of the bottom multiple-porous structure was reduced.