Abstract

High quality Al_1-xGa_xN/Al_1-yGa_yN multiple quantum wells (MQWs) with sharp interfaces and emitting at ~280 nm was successfully grown on sapphire substrate with a misorientation angle as large as 4°. Wavy MQWs are observed due to step bunching formed at the step edges of the highly misoriented substrate. A significantly enhanced photoluminescence intensity (at least 10 times higher), improved internal quantum efficiency over 90%, and a much longer carrier lifetime were achieved for QWs grown on 4° misoriented sapphire substrate when compared with that grown on 0.2° misoriented sapphire. Importantly, the wafer-level output power of the ultraviolet light emitting diodes on 4° misoriented sapphire substrate were nearly doubled. The compositional modulation in active region arising from the substrate misorientation provides a promising approach in the pursuit of future high-efficient UV emitters.

© 2020 The Author(s)