Enhancement of band-edge emission of ZnO from one-dimensional ZnO/MgZnO core/shell nanostructures

One-dimensional MgZnO nanostructures were grown directly on p-Si substrates by thermal evaporation at a variety of synthesis temperatures. Transmission electron microscopy and energy dispersive x-ray spectroscopy analysis revealed the formation of slim ZnO nanowires with twin boundaries on low Mg content nanosheets at lower synthesis temperatures, where the slim nanowires on the nanosheet did not have any detectable Mg content. The MgZnO nanostructures at elevated synthesis temperatures showed core/shell structures consisting of h-ZnO/h-MgZnO/c-MgZnO, where the h-MgZnO layer has a Mg content up to ∼9 at% and a further increase in Mg content in the outer shell induced the formation of the c-MgZnO phase. The ZnO nanorods covered with MgZnO layers showed enhanced band-edge emission due to the existence of a h-MgZnO barrier and a c-MgZnO dielectric layer.