Characterization of gallium nitride (GaN) blue LEDs

Commercially available GaN blue LEDs have been characterized for use as light sources for chemical sensors. These new LEDs are a double heterojunction structure of InGaN/AlGaN that have a peak output at 450 nm. Other groups have investigated these devices for full color displays. This investigation addresses parameters critical to chemical sensors. Several different paramters were characterized including spectra verses drive current, spectra before and after aging, output power verses drive current, and lifetime. The results of this characterization indicate that these devices perform well for some chemical sensors.