Energy Efficiency Analysis of GaN-Based Blue Light Emitters

Abstract

GaN-based light sources are in high demand for lighting, displays, medical equipment and other applications. InGaN/GaN blue light-emitting diodes (LEDs) reach an electrical-to-optical power conversion efficiency of more than 80% but less than 10% are reported for blue superluminescent light-emitting diodes (SLEDs) and less than 50% for blue laser diodes (LDs). We here analyze the physical mechanisms behind this surprising discrepancy in peak energy efficiency of GaN-based light emitters. Our study reveals that the Mg-doping of group-III-nitride layers, which was pioneered by Isamu Akasaki and collaborators, plays a key role in understanding this efficiency difference.