Select the sequential order of the procedure for ZnO nanorod synthesis using the CVD method.

Select the sequential order of the procedure for ZnO nanorod synthesis using the CVD method. Correct Answer Metallic zinc placed on alumina ➔ Temperature increased above 450°C ➔ Quartz vial filled with Zn vapour ➔ Au droplets supersaturated with Zn vapour ➔ ZnO nucleation

Granulated zinc of high purity is placed on alumina and kept inside a quartz ampoule sealed at one end. The entire setup is inside a quartz tube that is rapidly heated in a thermal furnace. Gold is used as a catalyst in this process. As soon as the temperature goes beyond the melting point of zinc (420°C), it vaporizes to fill the quartz vial. Catalyst forms liquid droplets to supersaturate the zinc vapours. ZnO nucleation growth is initiated upon the introduction of oxygen gas. Thus, ZnO precipitates when the droplets reach a critical radius. Finally, desired ZnO nanorods are obtained.