Into The Void: Boosting LED Energy Efficiency

LEDs are already vaunted as an energy-efficient technology for lighting, but new research shows that their efficiency can be increased by a factor of two. A paper describing the work shows that the secret is to decrease the number of defects in the gallium nitride (GaN) films used to create LEDs by incorporating cleverly placed voids into the films themselves.

To understand how empty space can boost energy efficiency, we need to understand what a defect is in this context. Picture a defect as a crack in your windshield. It starts out pretty small, but it spreads. And it keeps spreading until it hits the edge of the windshield. It doesn’t have room to spread any more, so it stops.

The defects in GaN films work the same way. They are slight dislocations in the crystalline structure of the material that spread until they reach the surface. By placing voids – simple, empty spaces – in the middle of the GaN film’s thickness, researchers from NC State were able to stop these defects from spreading. They’re simply cut off from continuing their trip to the surface.

Incorporating these voids into the films results in a significant decrease in defects – we’re talking two to three orders of magnitude. The higher quality of these films, in turn, boosts the power/light ratio. So, for a given amount of power put into the device, the output of light increases by a factor of two.

You can use half as much power, but won’t see any difference in the light.