Development of Key Technologies for White Lighting Based on Light-Emitting Diodes (LEDs)

Technical Report · Wed Mar 31 04:00:00 EST 2004

DOI:https://doi.org/10.2172/921943· OSTI ID:921943

Goetz, Werner ^[1]; Imler, Bill; Kim, James; Kobayashi, Junko; Kim, Andrew; Krames, Mike; Mann, Rick; Mueller-Mach, Gerd; Munkholm, Anneli; Wierer, Jonathan

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1. [e-mail]

This program was organized to focus on materials development issues critical to the acceleration of solid-state lighting, and was split into three major thrust areas: (1) study of dislocation density reduction for GaN grown on sapphire using 'cantilever epitaxy', and the impact of dislocation density on the performance of state-of-the-art high-power LEDs; (2) the evaluation of in situ techniques for monitoring gas phase chemistry and the properties of GaN-based layers during metal-organic vapor phase epitaxy (MOCVD), and (3) feasibility for using semiconductor nanoparticles ('quantum dots') for the down-conversion of blue or ultraviolet light to generate white light. The program included a partnership between Lumileds Lighting (epitaxy and device fabrication for high power LEDs) and Sandia National Laboratories (cantilever epitaxy, gas phase chemistry, and quantum dot synthesis). Key findings included: (1) cantilever epitaxy can provide dislocation density reduction comparable to that of more complicated approaches, but all in one epitaxial growth step; however, further improvements are required to realize significant gains in LED performance at high drive currents, (2) in situ tools can provide detailed knowledge about gas phase chemistry, and can be used to monitor and control epitaxial layer composition and temperature to provide improved yields (e.g., a fivefold increase in color targeting is demonstrated for 540nm LEDs), and (3) quantum efficiency for quantum dots is improved and maintained up to 70% in epoxy thin films, but further work is necessary to increase densification (absorption) and robustness before practical application to LEDs.

• Research Organization: Lumileds Lighting Us Llc
• Sponsoring Organization: USDOE
• DOE Contract Number: FC26-01NT41251
• OSTI ID: 921943
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
36 MATERIALS SCIENCE
COLOR
DESIGN
DISLOCATIONS
FABRICATION
GALLIUM NITRIDES
LIGHT EMITTING DIODES
LIGHTING SYSTEMS
PERFORMANCE
QUANTUM DOTS
QUANTUM EFFICIENCY
VAPOR PHASE EPITAXY