Room temperature hydrogen gas sensor based on ZnO nanorod arrays grown on a SiO2/Si substrate via a microwave-assisted chemical solution method

High-quality zinc oxide (ZnO) nanorod arrays were grown on a silicon dioxide (SiO2/Si) substrate via a microwave irradiation-assisted chemical solution method. The SiO2/Si substrate was seeded with polyvinyl alcohol–Zn (OH)2 nanocomposites prior to the complete growth of ZnO nanorods through a chemical solution method. X-ray diffraction, field-emission scanning electron microscope, and photoluminescence results indicated the high quality of the produced ZnO nanorods. The hydrogen (H2)-sensing capabilities of the ZnO nanorod arrays were investigated at room temperature (RT), and the sensitivity was 294% in the presence of 1000 ppm of H2. The sensing measurements for H2 gas at various temperatures (25–250 °C) were repeatable for over 100 min. The sensor exhibited a sensitivity of 1100% at 250 °C upon exposure to 1000 ppm of H2. Hysteresis was observed in the sensor at different H2 concentrations at different temperatures. Moreover, the response times ranged from 60 to 25 s over the range of operating temperatures from RT to 250 °C.

► Highly quality ZnO nanorods arrays were grown on SiO2 substrate using chemical solution. ► We use PVA–Zn(OH)2 nanocomposites as seed layer to grow ZnO nanorods. ► ZnO nanorods arrays show good sensitivity at room temperature to H2 gas.