Efficiency-enhanced AlGaInP Light-Emitting Diodes with Thin Window Layers and Coupled Distributed Bragg Reflectors

A new structure of high-brightness light-emitting diodes (LED) is experimentally demonstrated. The thin window layer is composed of a 300-nm-thick indium-tin-oxide layer and a 500-nm-thick GaP layer for both current spreading and light anti-reflection. The two coupled distributed Bragg reflectors (DBRs) with one for reflecting normal incidence light and the other for reflecting inclined incidence light which is emitted to the GaAs substrate are employed in the LED fabrication. The coupled DBRs in the LED can provide high reflectivity with wide-angle reflection. The efficiency-enhanced AlGaInP LED has the luminance intensity increase of more than 50% compared with conventional LEDs and high reliability with the saturation current 130 mA.