Self-enhanced controllable growth of ZnO micro-flowers from nanospikes and its transformation to nanoparticles by using compositional variation: Essential dielectric switching applications

We are reporting a large scale distribution of zinc oxide nanospikes of length from 745 to 900 nm those were grown as a micro-flowers with diameter of 1.2 μm. At low temperature, nanocapsules of diameter 186 nm and length 576 nm were gathered along with nanorods of diameter ranging from 644 to 966 nm and those were obtained by the variation of chemical composition of capping reagent hydrazine hydrate. By introducing a surfactant cetyltrimethylammonium bromide instead of hydrazine, we obtained uniform sized nanoparticles of diameter 150 nm with well crystallinity by applying high temperature and pressure inside the stainless steel autoclave. A detailed study of optical properties and dielectric spectra revealed a low threshold voltage with 0.45 V for nanoparticles in compare to higher threshold voltage 4 V for nanospikes having dielectric constant 1.9. We also observed a bi-stable dc switching capability of such nanostructures.