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.