Using the Taguchi method to improve the brightness of AlGaInP MQW LED by wet oxidation

To increase the external quantum efficiency of a light-emitting diode (LED) while limiting its forward voltage (V f ), we prepared both (Al x Ga 1-x ) 0.5 In 0.5 P LED and buried oxides through selective wet oxidation of the AlAs layers of AlAs-GaAs distributed Bragg reflectors. The wet oxidation process forms a stable Al x O material that acts as an insulation layer and affects both the carrier and optical confinements. To determine the tradeoff conditions for LED oxidation, we used the Taguchi method which is a robust technique that is often used to analyze significant trends that occur under a set of oxidation conditions. In this study, we used an L 9 orthogonal array to measure the effects that a series of factors have upon the maximum brightness performance of the LED in an effort to limit the values of V f . Relative to the as-grown LED, the oxidized LED that had been treated under the tradeoff wet-oxidation conditions displayed a sharply enhanced brightness (62.4% increase) in conjunction with only a slightly increased value of V f (only a 24.5% increase)