Improved Light Output of Photonic Crystal Light-Emitting Diode Fabricated by Anodized Aluminum Oxide Nano-Patterns

A photonic crystal (PC) light-emitting diode (LED) was fabricated using an anodized aluminum oxide (AAO) nano-pattern technique, which has potential applications to mass production. The AAO nano-pattern, which was anodized in 0.3-M oxalic acid at 70 V, was transferred to the n-GaN bottom cladding through reactive ion etching and covered during the regrowth of GaN to form periodic air holes. The PC was embedded into the bottom cladding, which resulted in a low operating voltage. For the PC LED, the light output was enhanced by more than 20%, while the operating voltage increased only slightly. The radiation pattern of the PC LED showed two lobes at approximately plusmn30deg, which originated from the diffraction by PC.