Controlled Synthesis of ZnO Nanostructures: The Role of Source and Substrate Temperatures

A shape diagram of ZnO nanostructures grown by thermal evaporation of a ZnO:C powder (carbothermal method) was derived by varying the powder source temperature (Tp) and the substrate temperature (Ts). All other growth parameters including (1) the carrier gas composition, pressure, and flow, (2) the substrate and catalyst type, and (3) the system geometry were kept constant. Comparative selected growth experiments utilizing a laser ablation system were performed to establish the general nature of the results. The roles of Ts and Tp in the evolution of the ZnO morphology and the mechanisms leading to the different morphologies were highlighted.