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Trade-off between bandwidth and efficiency in semipolar (202¯1¯) InGaN/GaN single- and multiple-quantum-well light-emitting diodes
- Source :
- Applied Physics Letters. 112:191102
- Publication Year :
- 2018
- Publisher :
- AIP Publishing, 2018.
-
Abstract
- InGaN/GaN light-emitting diodes (LEDs) with large modulation bandwidths are desirable for visible-light communication. Along with modulation speed, the consideration of the internal quantum efficiency (IQE) under operating conditions is also important. Here, we report the modulation characteristics of semipolar (202¯1¯) InGaN/GaN (LEDs) with single-quantum well (SQW) and multiple-quantum-well (MQW) active regions grown on free-standing semipolar GaN substrates with peak internal quantum efficiencies (IQEs) of 0.93 and 0.73, respectively. The MQW LEDs exhibit on average about 40–80% higher modulation bandwidth, reaching 1.5 GHz at 13 kA/cm2, but about 27% lower peak IQE than the SQW LEDs. We extract the differential carrier lifetimes (DLTs), RC parasitics, and carrier escape lifetimes and discuss their role in the bandwidth and IQE characteristics. A coulomb-enhanced capture process is shown to rapidly reduce the DLT of the MQW LED at high current densities. Auger recombination is also shown to play little role in increasing the speed of the LEDs. Finally, we investigate the trade-offs between the bandwidth and efficiency and introduce the bandwidth-IQE product as a potential figure of merit for optimizing speed and efficiency in InGaN/GaN LEDs.
- Subjects :
- 010302 applied physics
Materials science
Physics and Astronomy (miscellaneous)
Auger effect
business.industry
Bandwidth (signal processing)
02 engineering and technology
021001 nanoscience & nanotechnology
01 natural sciences
law.invention
symbols.namesake
law
0103 physical sciences
symbols
Optoelectronics
Figure of merit
Quantum efficiency
Parasitic extraction
0210 nano-technology
business
Quantum
Diode
Light-emitting diode
Subjects
Details
- ISSN :
- 10773118 and 00036951
- Volume :
- 112
- Database :
- OpenAIRE
- Journal :
- Applied Physics Letters
- Accession number :
- edsair.doi...........d44b5b63679e03e1e94fab6178697081