Phosphor-Free Solid-State Lighting Sources
Investigating Organization
Cermet Inc.
Principal Investigator(s)
Mr. Jeff Nause
Subcontractor
Georgia Tech
Funding Source
Building Technologies Program/NETL
Award
DOE Share: $3,840,370; Contractor Share: $971,239
Contract Period
09/30/03 - 02/28/07
Cermet's work focuses on growing conventional materials on novel substrates that possess unique physical properties with less internal strain. This process has the potential to increase efficiency; have emissions that can be adjusted by carefully applying potentials across the substrate; and can be made to behave like a phosphor, absorbing photons of one color and emitting new ones that are of a different color.
The goal of Cermet's effort is to implement large-area zinc oxide fluorescent substrate technology and state-of-the-art, lattice-matched nitride epitaxy technology to address substrate, epitaxy, and device limitations in the high growth area of solid state lighting. Cermet, in collaboration with researchers at Georgia Institute of Technology, will bring several technological innovations to the marketplace, including the following:
1. Truly lattice matched, low defect density (as low as 104 cm2) nitride emitter structures resulting in significantly reduced non-radiative recombination centers. This goal will be achieved by combining molecular beam epitaxy (MBE) and metallorganic chemical vapor deposition (MOCVD) with a ZnO substrate that is lattice matched to nitride LEDs in the wavelength range of 330 to 420 nm. Shorter wavelength designs are also possible using strain compensated layer growth.
2. White light emission via a self-fluorescing mechanism in the ZnO substrate. This will be accomplished by doping the ZnO substrates to yield emission in the vision spectrum. Optical pumping of the substrate will be achieved with the integrated nitride emitter.
3. Ability to adjust the color content of the white light. This will be achieved by adjusting the doping concentration of the substrate.