June 14, 2012
Efficiency Enhanced When LEDs Relocated From Silicon To Copper
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.
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