Improved InGaN LED System Efficacy and Cost via Droop Reduction
- Lumileds LLC, San Jose, CA (United States)
Efficiency droop is a non-thermal process intrinsic to indium gallium nitride light emitting diodes (LEDs) in which the external quantum efficiency (EQE) decreases with increasing drive current density. Mitigating droop would allow one to reduce the size of LEDs driven at a given current or to drive LEDs of given size at higher current while maintaining high efficiencies. In other words, droop mitigation can lead to significant gains in light output per dollar and/or light output per watt of input power. This project set an EQE improvement goal at high drive current density which was to be attained by improving the LED active region design and growth process following a droop mitigation strategy. The interactions between LED active region design parameters and efficiency droop were studied by modeling and experiments. The crystal defects that tend to form in more complex LED designs intended to mitigate droop were studied with advanced characterization methods that provided insight into the structural and electronic properties of the material. This insight was applied to improve the epitaxy process both in terms of active region design and optimization of growth parameters. The final project goals were achieved on schedule and an epitaxy process leading to LEDs with EQE exceeding the project target was demonstrated.
- Research Organization:
- Lumileds LLC, San Jose, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Brookhaven National Lab. (BNL), Upton, NY (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
- DOE Contract Number:
- EE0007136
- OSTI ID:
- 1410608
- Report Number(s):
- DOE-LL-0007136-3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mitigating Structural Defects in Droop-Minimizing InGaN/GaN Quantum Well Heterostructures
Improved InGaN LED System Efficacy and Cost via Droop Reduction (Final CRADA Report)