January 26, 2011 — Light-emitting diodes (LEDs) are an increasingly popular technology for use in energy-efficient lighting. Researchers from North Carolina State University have now developed a new technique that reduces defects in the gallium nitride (GaN) films used to create LEDs, making them more efficient.

LED lighting relies on GaN thin films to create the diode structure that produces light. The new technique reduces the number of defects in those films by two to three orders of magnitude. "This improves the quality of the material that emits light," says Dr. Salah Bedair, a professor of electrical and computer engineering at NC State and co-author, with NC State materials science professor Nadia El-Masry, of a paper describing the research. "For a given input of electrical power, the output of light can be increased by a factor of two." This is particularly true for low electrical power input and for LEDs emitting in the ultraviolet range.

Figure. The new technique reduces the number of defects in those films by two to three orders of magnitude — increasing the output of light by a factor of two for a given amount of power. (Image courtesy of Lukasz Tylec)

The researchers started with a GaN film that was 2