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Trace Metal Recombination Centers Kill LED Efficiency

posted by cmn32480 on Tuesday November 08 2016, @12:14AM   
from the dim-bulb dept.

Phoenix666 writes:

Using cutting-edge first-principles calculations, researchers at the University of California, Santa Barbara (UCSB) have demonstrated the mechanism by which transition metal impurities -- iron in particular -- can act as nonradiative recombination centers in nitride semiconductors. The work highlights that such impurities can have a detrimental impact on the efficiency of light-emitting diodes (LEDs) based on gallium nitride or indium gallium nitride.

For LEDs, high-purity material is essential to lighting technology, such as residential and commercial solid-state lighting, adaptive lighting for automobiles, and displays for mobile devices. Imperfections at the atomic scale can limit the performance of LEDs through a process known as Shockley-Read-Hall recombination. The operation of an LED relies on the radiative recombination of electrons and holes, which results in the emission of photons. Defects or impurities can act as a source of nonradiative recombination and prevent the emission of light, lowering the LED efficiency.

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Original Submission

• More interesting than I thought More interesting than I thought (Score: 5, Informative) by Mykl on Tuesday November 08 2016, @01:47AM

  by Mykl (1112) on Tuesday November 08 2016, @01:47AM (#423890)

  The really interesting bit about this article isn't that Iron impurities affect LED efficiency - the article and summary already state that this is well known. What's interesting is that they didn't know why Iron did this, as the conventional understanding of the Shockley-Read-Hall process suggested that it wouldn't.

  TL:DR - while Iron itself is fine, Iron in an excited state is a major problem.

  Starting Score:	1		point
  Moderation		+4
  Insightful=2, Informative=2, Total=4
  Extra 'Informative' Modifier		0
  Karma-Bonus Modifier		+1
  Total Score:		5

• Re:More interesting than I thought (Score: 2) by JoeMerchant on Tuesday November 08 2016, @02:30AM

  by JoeMerchant (3937) on Tuesday November 08 2016, @02:30AM (#423902)

  So, if you want to be bright: calm your iron?

  --
  🌻🌻 [google.com]

  Parent

• Re:More interesting than I thought (Score: 3, Funny) by bob_super on Tuesday November 08 2016, @02:31AM

  by bob_super (1357) on Tuesday November 08 2016, @02:31AM (#423903)

  > Iron in an excited state is a major problem

  It's an LED, it can blink the safe word.

  Parent

• Re:More interesting than I thought (Score: 0) by Anonymous Coward on Tuesday November 08 2016, @03:23PM

  by Anonymous Coward on Tuesday November 08 2016, @03:23PM (#424097)

  What I like about semiconductors is that for them to work, you need to dope them with impurities, but to make good ones you need to make sure your impurities are very pure.

  Parent