History of ZnO Nanostructures Synthesis methods

ZnO is traditionally synthesized at high temperatures in the gas phase .Huang et al .first reported the VLS catalytic growth of ZnO nanowires by vapor transport using an Au catalyst on Si substrates in 2001.

Others used catalyst-free vapor –soil processes such as mental-organic chemical vapor deposition ,These methods can produce high-quality, single-crystalline nanowires with high aspect ratios, but are limited in terms of sample uniformity, low product yield and ,most  notably ,substrate choice.

Wet chemical methods are an attractive alternative to vapor transport processes since they can be carried out at temperatures as low as 50℃，In solution at temperatures of less than 80℃. About 10 years later, others ZnO nanorod arrays. Typically, an aqueous and reported well-oriented C6H12N4 is heated to temperatures, In generally, HMTA decomposes into ammonia and formaldehyde. The ammonia provides a steady sources of hydroxide ions to form zinc hydroxide. Finally, the hydroxide compound undergoes a condensation reaction to form ZnO.

ZnO Application

Because it is difficult to manipulate such small structures, aligned growth is an efficient approach to self-assemble nanowires into useful devices such as nanowire lasers, light-emitting diodes, solar cells, water-splitting photocatalysts , nanogenerators, piezotriggers and field-effect transistors. The substrate is a crucial factory in the determining the nanowire must be satisfied between ZnO and the underlying substrate, As a result, substrate candidates must have wurtzite crystal structures similar to ZnO, such as sapphire, GaN, ALGaN or ALN. The substrate choices needed for high-temperature vapor transport synthesis are quite limited and unsuitable for polymers.