Optimized Microcavity and Photonic Crystal Parameters of GaN-Based Ultrathin-Film Light-Emitting Diodes for Highly Directional Beam Profiles

This study experimentally investigates the highly directional far-field emission distributions of GaN ultrathin-film light-emitting diodes (uTFLEDs) with optimized microcavity thickness and photonic crystal (PhC) parameters. Results show that directionality depends on guided mode extraction behaviors and strong microcavity effects. The proposed GaN PhC uTFLED exhibited an output power extraction efficiency enhancement of 278% (
${\sim}3.78\times$
) compared to GaN non-PhC uTFLED, and produced a directional far-field emission pattern at half intensity near
${\pm}$
17
$^{\circ}$
.