Self-organized ZnAl2O4 nanostructures grown on cc-sapphire

Self-organized ZnAl2O4 nanostructures with the appearance (in SEM) of high aspect ratio horizontal nanowires are grown on uncatalysed cc-sapphire by vapour phase transport. The nanostructures grow as three equivalent crystallographic variants on cc-sapphire. Raman and cathodoluminescence spectroscopy confirm that the nanostructures are not ZnO and TEM shows that they are the cubic spinel, zinc aluminate, ZnAl2O4, formed by the reaction of Zn and O with the sapphire substrate.