Electrical properties of relaxed p-GaN/p-AlGaN superlattices and their application in ultraviolet-B light-emitting devices

Abstract

Abstract The relaxation ratio of p-GaN/p-AlGaN superlattices was controlled by using different AlGaN underlying layers and the effects of relaxation on the electrical properties were investigated. High hole concentrations over 1 × 1018 cm−3 at room temperature and low activation energies below 120 meV were obtained regardless of the relaxation ratio. Using a p-GaN/p-Al0.5Ga0.5N superlattice, current injection at 1 A corresponding to 33.3 kA cm−2 was achieved without a significant drop in output power in an ultraviolet-B light-emitting diode including undoped AlGaN waveguide layers.