Fabrication of Hybrid n-ZnMgO/n-ZnO/ p-AlGaN/ p-GaN Light-Emitting Diodes

We report on the fabrication of UV light-emitting diodes (LEDs) based on a p – n junction n -ZnMgO/ n -ZnO/ p -AlGaN/ p -GaN semiconductor triple-heterostructure. Radio-frequency plasma-assisted molecular beam epitaxy was used to grow the complete heterostructure on p -AlGaN/ p -GaN c -plane sapphire templates. Cross-sectional transmission electron microscopy showed single-crystal quality of the pseudomorphically grown ZnO active region of the device. The LEDs were fabricated by a process involving both wet and dry etching. Electroluminescence emission most likely associated with ZnO excitonic transition was observed up to 370°C. The results show the potential of ZnO-based materials for UV emitters of potentially lower cost and with comparable or higher emission intensity than comparable AlGaN/GaN devices.