Large single crystals (many cubic centimeters) can be grown by the gas transport (vapor-phase deposition), hydrothermal synthesis, Thin films can be produced by chemical vapor deposition, metalorganic vapour phase epitaxy, electrodeposition, pulsed laser deposition, sputtering, sol-gel synthesis, atomic layer deposition, spray pyrolysis, etc.Ordinary white powdered zinc oxide can be produced in the laboratory by electrolyzing a solution of sodium bicarbonate with a zinc anode. The zinc hydroxide upon heating decomposes to zinc oxide.This indirect method was popularized by Le Claire (France) in 1844 and therefore is commonly known as the French process.Its product normally consists of agglomerated zinc oxide particles with an average size of 0.1 to a few micrometers.In both cases, the zinc and oxide centers are tetrahedral, the most characteristic geometry for Zn(II).Zn O converts to the rocksalt motif at relatively high pressures about 10 GPa.Advantages associated with a large band gap include higher breakdown voltages, ability to sustain large electric fields, lower electronic noise, and high-temperature and high-power operation.The bandgap of Zn O can further be tuned to ~3–4 e V by its alloying with magnesium oxide or cadmium oxide. This problem originates from low solubility of p-type dopants and their compensation by abundant n-type impurities. Measurement of p-type in "intrinsically" n-type material is complicated by the inhomogeneity of samples.
Zn O has a relatively large direct band gap of ~3.3 e V at room temperature.Those properties are valuable in emerging applications for: transparent electrodes in liquid crystal displays, energy-saving or heat-protecting windows, and electronics as thin-film transistors and light-emitting diodes.Zn O reacts slowly with fatty acids in oils to produce the corresponding carboxylates, such as oleate or stearate.The hexagonal structure has a point group 6 mm (Hermann-Mauguin notation) or C as well as the strong piezoelectricity of Zn O.Because of the polar Zn-O bonds, zinc and oxygen planes are electrically charged.