Blue (In,Ga)N light-emitting diodes with buried n+–p+ tunnel junctions by plasma-assisted molecular beam epitaxy

Abstract

Blue LEDs consisting of a buried n+–p+ GaN tunnel junction (TJ), (In,Ga)N multiple quantum wells (MQWs) and a n+-GaN top layer are grown on Ga-polar n+-GaN bulk wafers by plasma-assisted molecular beam epitaxy. The (In,Ga)N MQWs show chemically abrupt and sharp interfaces in a wide range of compositions and are seen to have high structural and optical properties. The processed LEDs reveal clear rectifying behavior with a low contact and buried TJ resistivity. By virtue of the top n+-GaN layer with a low resistance, excellent current spreading in the LEDs is observed in this device structure.