Ultraviolet light emissions in MgZnO/ZnO double heterojunction diodes by molecular beam epitaxy

ZnO double heterojunction structure was grown by molecular beam epitaxy. 100 nm MgZnO/ZnO/MgZnO well was inserted between Ga-doped ZnO and Sb-doped ZnO layers. X-ray diffraction spectrum confirmed the preferential growth along c-direction and secondary ion mass spectroscopy measurements showed a clear double heterojunction profile of this structure. Thin MgZnO layers made no difficulties for electrons and holes to get into active intrinsic ZnO layer. Dominant ultraviolet electroluminescence was observed at the injection currents from 40 to 80 mA at room temperature. The output power was 7.3 times as that from p-n homojunction diode at the same driving current due to a good confinement of electrons and holes in the intrinsic ZnO layer. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3374436]