Room-temperature photoluminescence from ZnO∕ZnMgO multiple quantum wells grown on Si(111) substrates

A set of ten-period ZnO∕Zn0.85Mg0.15O multiple quantum wells with well thickness varying from 2.5to5nm has been grown on Si(111) substrates by pulsed laser deposition. A periodic structure with sharp interfaces was observed by cross-sectional transmission electron microscopy. The room-temperature photoluminescence resulting from the well regions exhibits a significant blueshift with respect to the ZnO single layer. The well layer thickness dependence of the emission energy from the well regions was investigated and compared with a simple theoretical model. The results suggest that the quantum confinement effects in the quantum wells can be observed up to room temperature.