III-nitride quantum dots for ultra-efficient solid-state lighting

• Published in: Laser & photonics reviews Vol. 10; no. 4; pp. 612 - 622
• Main Authors: Wierer Jr, Jonathan J., Tansu, Nelson, Fischer, Arthur J., Tsao, Jeffrey Y.
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.07.2016; Wiley Subscription Services, Inc; Wiley
• Subjects: Auger recombination; Augers; Current density; Devices; efficiency droop; ENGINEERING; GaN; III-nitride; Illumination; InGaN; laser diodes; LDs; LEDs; Light emitting diodes; Lighting; PC-LEDs; phosphor-converted; Quantum Dots; Quantum wells; Solid-state lighting
• ISSN: 1863-8880; 1863-8899
• DOI: 10.1002/lpor.201500332

III‐nitride light‐emitting diodes (LEDs) and laser diodes (LDs) are ultimately limited in performance due to parasitic Auger recombination. For LEDs, the consequences are poor efficiencies at high current densities; for LDs, the consequences are high thresholds and limited efficiencies. Here, we present arguments for III‐nitride quantum dots (QDs) as active regions for both LEDs and LDs, to circumvent Auger recombination and achieve efficiencies at higher current densities that are not possible with quantum wells. QD‐based LDs achieve gain and thresholds at lower carrier densities before Auger recombination becomes appreciable. QD‐based LEDs achieve higher efficiencies at higher currents because of higher spontaneous emission rates and reduced Auger recombination. The technical challenge is to control the size distribution and volume of the QDs to realize these benefits. If constructed properly, III‐nitride light‐emitting devices with QD active regions have the potential to outperform quantum well light‐emitting devices, and enable an era of ultra‐efficient solid‐state lighting. III‐nitride quantum dots (QDs) are investigated as active regions in both light‐emitting diodes and laser diodes in order to circumvent Auger recombination for improved performance. The lower transparency current densities and higher spontaneous emission rates in QDs results in higher efficiencies, and at much higher current densities compared to quantum wells (QWs). If synthesized properly, QD‐based light‐emitting devices could enable an era of ultra‐efficient solid‐state lighting.