Pushing Photons: Metasurface design methods can make LED light act more like lasers

Researchers at the University of California, Santa Barbara have described a new method that could pave the way toward more efficient and versatile light-emitting diode (LED) display and lighting technology. Light in LEDs is generated in a semiconductor material when excited electrons traveling along the semiconductor’s crystal lattice meet holes (an absence of electrons) and transition to a lower state of energy, releasing a photon along the way. Over the course of their measurements, the researchers found that a significant amount of these photons were being generated but were not making it out of the LED. The researchers designed an array of gallium nitride nanorods on a sapphire substrate, in which quantum wells of indium gallium nitride were embedded, to confine electrons and holes and thus emit light.