Growth of zinc oxide nanostructures on glass substrates for ethanol gas sensor application

ZnO nanostructures grown on glass (SiO2) substrates have been successfully fabricated for ethanol gas sensor. These ZnO nanostructures were prepared by chemical bath deposition with various ammonium hydroxide concentrations. The response of ZnO - based ethanol gas sensor exhibited higher response at lower NH4OH concentration; this might be attributed to the uniform morphology of the ZnO nanostructures which facilitates easier interaction with the ethanol gas. On the other hand, at higher NH4OH concentration showed drastic decrease in sensor response. This might be due to the growth of broken nanorods. Scanning electron microscope (SEM) images confirmed the formation of uniform and vertically grown nanostructures with lower concentration of NH4OH. On the other hand, at higher NH4OH concentration, broken nanorods and agglomerations were present as revealed in the SEM micrographs. Energy dispersive x-ray spectroscopy (EDS) measurements suggested that the grown nanostructures were most likely composed of ZnO. The calculated energy band gap from the UV-Vis spectra confirmed that the grown ZnO nanostructures.