Relocating LEDs from silicon to copper enhances efficiency

June 14, 2012

Chinese researchers have succeeded in transferring gallium nitride (GaN) light-emitting diodes (LEDs) grown on a layer of silicon to a layer of copper.

The new copper substrate enabled the GaN crystals to release some of the internal stresses generated when they originally formed. This relaxation helped minimize the so-called "quantum confined stark effect," a vexing problem for LEDs that reduces their efficiency. In comparison with LEDs on silicon substrates, the light output of LEDs on copper was enhanced by 122 percent. The relocation of the LEDs produced no obvious deterioration in the crystals' light-emitting region, known as multiple .

The researchers attributed the improvements in efficiency to the removal of the absorptive substrate; the insertion of a metal reflector between the LEDs' structure and the copper submount; the elimination of electrode shading, which also reduces efficiency; and the rough surface of the exposed buffer layer, which improves crystal orientation on the substrate. The results are reported in a paper accepted for publication in the American Institute of Physics' journal .

Explore further: Silicon, nitride LEDs integrated onto a single chip for one-bit digital counters

More information: "Crack-free InGaN multiple quantum wells light-emitting diodes structures transferred from Si (111) substrate onto electroplating copper submount with embedded electrodes" Applied Physics Letters.

Related Stories

Nanowires offer opportunities for improved LEDs

July 1, 2011

Researchers from Dutch FOM Institute AMOLF, together with colleagues from Philips Research, Eindhoven University of Technology and Delft University of Technology, have made special nanostructures that could be used as light-emitting ...

Soraa LED light may dim 50-watt halogen rivals

February 9, 2012

(PhysOrg.com) -- Soraa, a Fremont, California company founded in 2008, this week launched its first product, a light that uses LEDS (light emitting diodes). The "Soraa LED MR16 lamp" is the "perfect" replacement for traditional ...

Conquering LED efficiency droop

April 30, 2012

WASHINGTON, April 30--Like a coffee enthusiast who struggles to get a buzz from that third cup of morning joe, light-emitting diodes (LEDs) seem to reach a point where more electricity no longer imparts the same kick and ...

LEDs on silicon can reduce production costs

May 21, 2012

A new manufacturing technology is expected to greatly reduce the cost of light-emitting diodes (LEDs) in the future. For the first time ever, researchers at the Siemens subsidiary Osram Opto Semiconductors were able to successfully ...

Recommended for you

Transforming living cells into tiny lasers

July 28, 2015

In the last few decades, lasers have become an important part of our lives, with applications ranging from laser pointers and CD players to medical and research uses. Lasers typically have a very well-defined direction of ...

New blow for 'supersymmetry' physics theory

July 27, 2015

In a new blow for the futuristic "supersymmetry" theory of the universe's basic anatomy, experts reported fresh evidence Monday of subatomic activity consistent with the mainstream Standard Model of particle physics.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.