Oxygen is indispensable to animal and plant life, but its presence in the wrong places can feed a fire and cause iron to rust. In the fabrication of solid state lighting devices, scientists are learning, oxygen also plays a two-edged role. While oxygen can impede the effectiveness of gallium nitride (GaN), an enabling material for LEDs, small amounts of oxygen in some cases are needed to enhance the devices’ optical properties. GaN doped with europium (Eu), which could provide the red color in LEDs and other displays, is one such case.
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