Growth analysis of novel ZnO nanotetrapods with tubular legs from aspect of reagent’s vapor pressure and growth temperature

In this article, novel ZnO nanotetrapods with tubular legs was successfully synthesized using mixed powder of Zn, ZnO, and carbon as source. The growth process was analyzed at large, and a two-step growth model, viz. initial deficient-oxidation and latter second-volatilization, was proposed to explain the formation of tubular leg of ZnO nanotetrapod. In the growth model, the high Zn vapor pressure and high growth temperature were considered as two crucial factors determining the growth behavior. Zn-rich ZnO nanotetrapod formed under high Zn vapor pressure at the initial stage. These redundant Zn clusters coexisted in ZnO lattice as interstitial Zn. The following second-volatilization of interstitial Zn under high growth temperature led to formation of tubular leg. Four other experiments were designed to analyze the growth behavior under high and low Zn vapor pressure and growth temperature, respectively, and these experimental results further confirmed the validity of our growth model. Our experiment proposed a feasible synthesis route to prepare hollow nanostructures controlled by the vapor pressure and growth temperature. Furthermore, these novel ZnO nanotetrapods might have potential application as building blocks for functional nanodevices.