Enhancement of light extraction from microstructured GaN-based light emitting diodes by technique of nanoimprint

To further improve surface light extraction from flip-chip GaN-based LED, the patterning of two-dimensional (2D) microstructural arrays on the top of the LED was proposed in this report. Based on this proposal, the novel LEDs covered by thin encapsulations with microstructure-arrays were successfully fabricated by employing the nanoimprint technique of embossing of thermosetting polymers. As a result, a clear enhancement of surface light extraction was obtained in the LEDs with encapsulations of micro-arrays. A 60% improvement of light output was achieved on these 1 mm ?? 1 mm GaN based LEDs under injection current of 350 mA. Consequently, this work provides an available and simplified approach to increase the extraction efficiency of LEDs.EI0SUPPL.464-4662