Nanoflower-like ZnO films prepared by modified chemical bath deposition: Synthesis, optical properties and NO2 gas sensing mechanism

In the present work, nanoflower-shape zinc oxide (ZnO) films synthesized by modified chemical bath deposition (CBD). The optimum working temperature and pH was determined 50±5 °C and 9.8, respectively. Conditioning solution can functioned as an adhesive in CBD process which have been used for the first time. The effect of annealing temperature (450, 500 and 550 °C) was studied and the changing structural, elemental and morphological properties were investigated by using XRD, EDX and SEM devices, respectively. All polycrystalline films had [002] preferential orientation and the maximum crystallization was observed in ZnO films that annealed at 500 °C. Detailed optical properties (absorption, band gap energy) were investigated by using Uv-Vis spectroscopy. Optical transmittance spectra showed high optical absorption below to 370 nm in the range 300-900 nm. Gas sensing mechanism for 0.5 ppm NO2 gas was investigated by using home-made gas sensing chamber that sensor working at 200 °C and nano-flower dimensions severly affected to gas sensitivities. © 2017, Inst Materials Physics. All rights reserved.