HIGH-LUMINOSITY BLUE AND BLUE-GREEN GALLIUM NITRIDE LIGHT-EMITTING-DIODES

Compact and efficient sources of blue tight for full color display app lications and lighting eluded and tantalized researchers for many year s. Semiconductor light sources are attractive owing to their reliabili ty and amenability to mass manufacture. However, large band gaps are r equired to achieve blue color. A class of compound semiconductors form ed by metal nitrides, GaN and its allied compounds AlGaN and InGaN, ex hibits properties well suited for not only blue and blue-green emitter s, but also for ultraviolet emitters and detectors. What thwarted engi neers and scientists from fabricating useful devices from these materi als in the past was the poor quality of material and lack of p-type do ping. Both of these obstacles have recently been overcome to the point where high-luminosity blue and blue-green light-emitting diodes are n ow available in the marketplace.