Effect of Mg Doping on the Structural, Optical and NO<sub>2</sub>-sensing Properties of ZnO Thin Films Prepared by Modified SILAR Method

In this report, we have prepared undoped and Mg-doped ZnO thin films by a modified successive ionic layer adsorption reaction (SILAR) method. The structural, surface morphological, chemical compositional, optical properties of pure were characterized X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), ultraviolet-visible (UV-VIS) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy. XRD patterns doped wurtzite crystal structures with preferential orientation along the (101) plane, without any secondary phases. Addition Mg into host influenced morphology film. Predominant nanorods-like turned to be predominant nanoflowers-like after addition Mg. UV-VIS spectra showed that band gap increased increase doping concentration. EDS FT-IR confirmed successful doping. Gas sensing tested based on electrical resistance changes upon exposure different concentrations NO2 gas at 200°C operating temperature. (3 wt%) higher response compared other wt% exhibited highest responses 2.95, 9.51, 9.93 when exposed 25, 50, 100 ppm 200°C, respectively. response/recovery time film 6/75, 14/88, 14/89 s ppm,