HIGH-BRIGHTNESS ALGAINP LIGHT-EMITTING-DIODES

First commercially introduced in 1990, AlGaInP light emitting diodes ( LED's) currently are the highest (luminous) efficiency visible solid-s tate emitters produced to date in the red through yellow spectral regi me. The attainment of this high-efficiency performance is a result of the development of advanced metalorganic chemical vapor deposition cry stal growth techniques, which have facilitated the high-quality growth of this quaternary alloy as well as the implementation of complex dev ice designs. Furthermore, the highest efficiency family of AlGaInP dev ices (based upon a transparent-substrate platform and commercially int roduced in 1994) have been realized as result of the development and i mplementation of direct compound semiconductor wafer bonding technolog y. As a result, the luminous efficiency of AlGaInP LED's exceeds or ri vals that of unfiltered incandescent lamps and other conventional ligh ting sources. Further improvements in these techniques (and the realiz ation of efficient, high-power LED's) are expected to make AlGaInP LED 's even more competitive with conventional lamp technology, thus enhan cing the position of LED's in many applications as a preferred lightin g source.