MBE-Grown CdZnO/ZnO Multiple Quantum-Well Light-Emitting Diode on MOCVD-Grown p-Type GaN

A CdZnO/n-ZnO multiple-quantum-well (QW) light-emitting diode (LED), with the QWs and
${\rm n}^{+}$
-ZnO capping layer grown with molecular beam epitaxy on p-GaN, which is grown with metal–organic chemical vapor deposition, is fabricated and characterized. Because of the weak carrier localization mechanism in the ZnO-based LED, its defect emission is quite strong and dominates the LED output when injection current is low. The blue shift of the LED output spectrum in applying a forward-biased voltage and the large blue-shift range in increasing injection current show the different behaviors of such a ZnO-based LED from those of a nitride LED.