ZnO nanowire growth by chemical vapor deposition with spatially controlled density on Zn2GeO4:Mn polycrystalline substrates

Aligned ZnO nanowires were successfully synthesized by CVD growth on polycrystalline Zn2GeO4:Mn substrates. The density of the nanowires was explored as a function of gold catalyst thickness as well as the geometry of the growth system. For the first time we demonstrated that the density of ZnO nanowires can be directly tailored by adjusting the lateral distance between a Zn2GeO4:Mn substrate and source powders, and symmetric growth was observed when source powders were placed both upstream and downstream in two separated zones during the synthesis process in a tube furnace. Electric field modelling was employed to predict a desired nanowire density range for future application of the Zn2GeO4:Mn/ZnO structures to electroluminescent devices.