Magnesium-Doped ZnO Nanorod Electrolyte–Insulator–Semiconductor (EIS) Sensor for Detecting Organic Solvents

Electrolyte–Insulator–Semiconductor (EIS) chemical sensor based on vertically aligned Mg doped ZnO nanorod is fabricated to detect different organic solutions at room temperature. The Mg doped ZnO nanorod was prepared by hydrothermal method over Si substrate. The X-ray diffraction (XRD) patterns and field emission scanning electron microscopy (FESEM) images confirm the Mg doped ZnO nanorods have good crystal quality and grow along with the (0 0 2) direction. Additionally, X-ray photoelectron spectroscopy (XPS) results suggest the existence of the Mg into ZnO crystal lattice. The sensing characteristics of Mg-doped ZnO nanorod toward detecting different organic solvents exhibit an excellent response to 2-methoxyethanol with a high sensitivity of 694 $\mu \text{V}$ /ppm, low drift rate of 0.062 mV/h and low limit of detection of 185 ppm. The selectivity results shows that the Mg doped ZnO nanorod is most selective to 2-methoxyethanol against acetone, ethanol and methanol.