ABSTRACT
Nanovolcanoes are very rare. Thus, ZnO nanovolcanoes (Figure 12.1), among other nanostructures, were grown1 (Reactions 12.1 through 12.4) using the hydrothermal technique from zinc nitrate and hexamethylenetetramine (HMT) as precursors. It was established that, by increasing the reaction time, the volcano-like and tube-like ZnO structures were formed due to the Ostwald ripening process and the selective adsorption of the complexes. In addition, the formation of large features at the edges of nanopores in freestanding silicon nitride membranes, called by authors “nanovolcanoes,” was studied.2 It was established that the rate at which the nanopores open or close was strongly in–uenced by sample temperature. In addition, volcano size and closing rates were found to be dependent on the initial pore size.
