Effect of GaN microlens array on efficiency of GaN-based blue-light-emitting diodes

In this study, GaN-based vertical light-emitting diodes (VLEDs) were fabricated by a laser lift-off (LLO) process and the effects of microlens formation by plasma etching on the optical properties of the LLO GaN-based VLED devices were investigated. By forming a 5-10 mu m microlens array on the LLO GaN-based VLEDs, the measured light emission intensities at 460 nm and in the direction normal to the surface of the device increased by approximately 40% and 100% compared with those of the LLO GaN-based VLED without the microlens array for 10 pm and 5 pm microlens arrays, respectively.