Image courtesy of American Physical Society.
Light-emitting diodes (LED) are not perfectly energy-efficient devices — in other words, not all the electrical energy is converted to light during its operation. Thus, LED’s experience undesired energy losses. In an LED, a few missing atoms at the gallium sites of the gallium nitride (GaN) crystal lattice are responsible for this loss. The artist’s rendering shows the crystal structure of GaN in front of the fabricated device structure of an LED. The light emission originates from the layered region shown in green.