Micro Cavity Effect in GaN-Based Light-Emitting Diodes Formed by Laser Lift-Off and Etch-Back Technique

Electroluminescence measurements were performed on GaN-based micro-cavity light-emitting diodes (MCLEDs) which had different cavity thickness. The MCLEDs were fabricated by laser lift off (LLO) technique to remove the sapphire substrate and were thinned with reactive ion etching (RIE) followed by chemical-mechanical polishing (CMP). The number of multiple peaks in the electroluminescence spectrum caused by interference effects decreased as the cavity thickness decreased. A far-field pattern measurement of the thin cavity sample showed a "rabbit ears" pattern, specific of microcavity emission.