Abstract
Five-fold stacked ZnO/ZnMgO quantum wells are fabricated by radical-source molecular beam epitaxy on a-plane sapphire, employing low-temperature growth for the ternary component and appropriate annealing steps performed at each interface. Transmission electron microscopy images reveal that the ZnO/ZnMgO interfaces are abrupt and smooth on an atomic scale. Threading dislocations originating from the interfacial region between substrate and the ZnMgO nucleation layer are largely annihilated during growth of a subsequent 600 nm thick ZnMgO buffer. The residual dislocation density in the well region is sufficiently low to allow for efficient exciton emission up to room temperature.
Export citation and abstract BibTeX RIS