Liquid-Phase Growth of Nanocrystalline ZnO Thin Films and Their Gas-Sensitive Properties

Films of nanocrystalline ZnO have been synthesized in situ on specialized substrates as a result of heat treatment of zinc acetylacetonate hydrate solutions in 1-butanol and ethylene glycol. It has been found that the morphology and coating integrity significantly depend on the solvothermal synthesis solvent. Thus, in ethylene glycol medium a coating with higher integrity and smaller size of ZnO nanoparticles is formed. The ZnO film obtained by [Zn(H 2 O)(O 2 C 5 H 7 ) 2 ] destruction in ethylene glycol demonstrates, as part of a chemical gas sensor, high selectivity and sensitivity to NO 2 throughout the temperature range with a maximum chemoresistive response at 250°C (the response to 4–100 ppm NO 2 is in the range 2.2–103). It is shown that as the detection temperature decreases, there is a change in the response direction as a result of various surface processes.