Energy Efficiency

Published on March 24th, 2014 | by James Ayre


Brighter, More Resilient LEDs Via New Processing Technique

March 24th, 2014 by  

Brighter and more resilient LEDs can be created via the use of a new processing technique developed by researchers from North Carolina State University.

The improvements are achieved by coating the semiconductor material gallium nitride (GaN) with a layer of phosphorus-derived acid.

By coating polar gallium nitride with phosphonic groups, the researchers increased luminescence without increasing energy input. Image Credit: Stewart Wilkins

By coating polar gallium nitride with phosphonic groups, the researchers increased luminescence without increasing energy input. Image Credit: Stewart Wilkins

“By coating polar GaN with a self-assembling layer of phosphonic groups, we were able to increase luminescence without increasing energy input,” states Stewart Wilkins, a PhD student at NC State and lead author of a paper detailing the new work. “The phosphonic groups also improve stability, making the GaN less likely to degrade in solution.

“Making the GaN more stable is important,” Wilkins continues, “because that makes it more viable for use in biomedical applications, such as implantable sensors.”

The press release from North Carolina State University provides the details:

The researchers started with polar GaN, composed of alternating layers of gallium and nitrogen. To increase luminescence, they etched the surface of the material with phosphoric acid. At the same time, they added phosphonic groups — organic molecules containing phosphorus — that self-assembled into a monolayer on the surface of the material. This layer further increased luminescence and improved the stability of the GaN by making it less likely to react chemically with its environment.

The new research paper describing the work — In Situ Chemical Functionalization of Gallium Nitride with Phosphonic Acid Derivatives during Etching — was published online in the journal Langmuir.

The work was supported in part by a grant from the National Science Foundation.

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

  • bussdriver78

    Now is this public info due to the taxpayer grant or will it be privately held (patent) for decades and add costs to manufacturing?

    • Bob_Wallace

      If it’s patentable then it will likely be licensed out to manufacturers who want to use it.

      The companies that lease the patent will likely have a leg up on other companies and the competition between them will force costs down.

  • JamesWimberley

    An infographic that adds nothing to the story.
    LEDs are already very tough and long-lived, The gain in efficiency is the more important aspect.

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