What limits the efficiency of GaN-based superluminescent light-emitting diodes (SLEDs)?
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Gallium-nitride-based SLEDs are attractive light sources for augmented reality displays and other applications. However, the electrical-to-optical power conversion efficiency (PCE) of SLEDs is still far below the record-high values reported for LEDs. Utilizing advanced numerical device simulation, this paper investigates the internal physical processes that cause the low PCE of SLEDs. The poor hole conductivity strongly reduces the electrical efficiency, similar to laser diodes. However, in contrast to laser diodes, the rising carrier density in the active layers is identified as main reason for enhanced Auger recombination that severely limits the internal quantum efficiency. Design improvement options are demonstrated.
KeywordsSuperluminescent light-emitting diode SLED Laser diode InGaN/GaN Power conversion efficiency Auger recombination Hole conductivity Self-heating
- Castiglia, A., Rossetti, M., Malinverni, M., Mounir, C., Matuschek, N., et al.: Recent progress on GaN-based superluminescent light-emitting diodes in the visible range. SPIE Proc. 10532, 1053421X (2018)Google Scholar
- Matuschek, N., Duelk, M.: In: Piprek, J. (ed.) Handbook of Optoelectronic Device Modeling and Simulation, vol. 19. CRC Press, Boca Raton (2017)Google Scholar
- Ohno, H., Orita, K., Kawaguchi, M., Yamanaka, K., Takigawa, S.: 200 mW GaN-based superluminescent diode with a novel waveguide structure. In: IEEE Photonics Conference, WN2 (2011)Google Scholar
- Piprek, J., Nakamura, S.: Physics of high-power InGaN/GaN lasers. IEE Proc. Optoelectr. 149, 145151 (2002)Google Scholar
- Piprek, J.: Semiconductor Optoelectronic Devices: Introduction to Physics and Simulation. Academic Press, San Diego (2003)Google Scholar