Acetic acid sensing of Mg-doped ZnO thin films fabricated by the sol–gel method

Abstract

Acetic acid vapor thin film gas sensor was developed by synthesizing Mg-doped ZnO nanoparticles using a low cost and facile sol–gel route and were characterized using field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and photoluminescence analysis. Morphological characterizations showed the formation of well-defined and highly crystalline ZnO nanoparticles on Si(100)/SiO2 substrate. Gas sensing characterization of dip coated Mg-doped ZnO thin films were performed in temperature range of 150–400 °C at different acetic acid vapor concentrations. At 300 °C, the sensitivity for pure ZnO, Zn0.98Mg0.02O and Zn0.94Mg0.06O samples at concentration of 200 ppm of acetic acid were 124, 78 and 67%, respectively. The highest sensitivity for Zn0.96Mg0.04O sample was 136% at the same vapor concentration and temperature. It showed a fast response time and recovery time (145 and 110 s, respectively).