An overview of visible light emitting diode (LED) development and the potential for AlInGaP devices

Recent developments in light-emitting diode (LED) materials growth and device properties are considered. The brightness of LEDs has increased in recent years, permitting new applications. Double heterostructure AlGaAs red LEDs on transparent 'substrates' are now commercially available for outdoor displays and signaling applications. Recently, AlInGaP LEDs grown by metalorganic chemical vapor disposition (MOCVD) have exhibited record performance in the yellow and red-orange spectral regions. External quantum efficiencies of greater than 5% and luminous performance as high as 20 lm/W at 590 nm have been reported. This performance is higher than that of conventional incandescent bulbs.