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Relocating LEDs from silicon to copper enhances efficiency

Date:
June 14, 2012
Source:
American Institute of Physics
Summary:
Chinese researchers have succeeded in transferring gallium nitride (GaN) light-emitting diodes (LEDs) grown on a layer of silicon to a layer of copper. In comparison with LEDs on silicon substrates, the light output of LEDs on copper was enhanced by 122 percent.
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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 quantum wells. 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 Applied Physics Letters.


Story Source:

The above post is reprinted from materials provided by American Institute of Physics. Note: Materials may be edited for content and length.


Journal Reference:

  1. Tufu Chen, Yunqian Wang, Peng Xiang, Ruihong Luo, Minggang Liu, Weimin Yang, Yuan Ren, Zhiyuan He, Yibin Yang, Weijie Chen, Xiaorong Zhang, Zhisheng Wu, Yang Liu, Baijun Zhang. 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, 2012; 100 (24): 241112 DOI: 10.1063/1.4729414

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American Institute of Physics. "Relocating LEDs from silicon to copper enhances efficiency." ScienceDaily. ScienceDaily, 14 June 2012. <www.sciencedaily.com/releases/2012/06/120614082633.htm>.
American Institute of Physics. (2012, June 14). Relocating LEDs from silicon to copper enhances efficiency. ScienceDaily. Retrieved September 3, 2015 from www.sciencedaily.com/releases/2012/06/120614082633.htm
American Institute of Physics. "Relocating LEDs from silicon to copper enhances efficiency." ScienceDaily. www.sciencedaily.com/releases/2012/06/120614082633.htm (accessed September 3, 2015).

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