Effect of n-Type AlGaAs Layer on Efficiency of Reflective 590-nm AlGaInP Light Emitting Diodes

Abstract

The effects of using an n-AlGaAs layer to improve the efficiency of wafer-bonded reflective 590 nm AlGaInP light-emitting diodes (LEDs) were investigated. This n-AlGaAs layer was grown on an optically absorbing substrate using metal organic chemical vapor deposition (MOCVD) during AlGaInP LED epitaxial growth. It was found that the inserted n-AlGaAs layer effectively acted as both an etching stop layer and ohmic contact layer. Here, the n-AlGaAs layer was located on the top layer of the reflective AlGaInP LED. As a result, a 1.2-fold relative increase in output power was observed from the reflective AlGaInP LED chip having the n-AlGaAs top layer. This increase was subsequently attributed to the increase in the current spreading effect due to insertion of the n-AlGaAs layer.