Zno nanostructures fabricated through a double-tube vapor-phase transport synthesis

A double-tube vapor-phase transport system has been used to synthesize ZnO nanostructures. Nanofeatures of ZnO nanocombs, nanoblades and nanowires were achieved in different temperature zones. The scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to study the nanostructure dependence with temperature. The vapor-liquid-solid (VLS) and vapor-solid (VS) growth mechanism are applied to explain the growth processes. ZnO two-sided nanocomb formed between 950 and 980 °C is dominated by VS growth. With growth temperature decreasing (820-950 °C), Au catalyst directed ZnO one-sided nanocombs and nanoblades growths are controlled by VLS and VS mechanisms. At low growth temperature zone between 710 and 820 °C, VLS growth dominates ZnO nanowire growth. A consistent orientation relationship between Au catalysts and ZnO nanocombs, nanoblades and nanowires is observed, i.e., 〈21¯1¯0〉ZnO//〈011〉Au and {011¯0}ZnO//{11¯1}Au. The growth mechanism has a strong relationship with growth temperature of the ZnO nanostructures. Understanding the relationship of growth mechanisms and nanostructures is very important for future controlled growth.