You may know semiconductors from computers: they’re a material somewhere between an electrical conductor and an electrical insulator that can be used as an extremely fast switch. However, semiconductors are also what we have to thank for the revolution in energy-efficient LED lighting technology.
“One of them is gallium nitride. The reason it's a good light bulb is, if you can excite an electron, say, with applying a voltage, then when it de-excites, it emits a photon. And these are the photons that make it a good light bulb.”
Kathy Kash is professor of physics at Case Western Reserve University. While the photons of white light from gallium nitride might have replaced many of the incandescent light bulbs in your own home, researchers like Kash are still seeking the rainbow.
“For lighting technology, what you really care about is spanning the red to the blue. And there's not yet a single material system that will do that efficiently.”
Kash and her group are working on the next step beyond gallium nitride semiconductors, adding a third element that could allow them to cover the entire rainbow with one material.
“However, controlling where those atoms go becomes also more complicated. That's a great deal of the effort that my students and I are putting in to developing these materials.”
