Room temperature blue LED based on p-ZnO/(CdZnO/ZnO) MQWs/ n-ZnO

Blue multiple quantum well light-emitting diodes comprising of p-ZnO/(Cd0.12Zn0.88O/ZnO) multiple quantum wells/n-ZnO were grown on n-Si substrates using dual ion-beam sputtering deposition technique. X-ray diffraction of individual thin films revealed growth preferentially in c-axis direction perpendicular to the substrate. Photoluminescence studies indicated blue emission ~ 440 nm from CdZnO and UV emission ~384 nm arising from ZnO thin films. The LED showed a rectifying current-voltage behavior with a turn-on voltage of ~4.69 V at room temperature. It emanated a room-temperature electroluminescence peak centered at 442 nm, along with shoulder peak at 380 nm in ultra-violet region associated with the recombination in ZnO layers of structure. It was found that with the increase in injection current the blue EL intensity increased and UV emission decreased, leading to improvement in successful radiative recombination in quantum wells. The results indicate prospects of fabrication of ZnO-based blue multiple quantum well LEDs.