Hydrogen gas sensing based on ZnO nanostructure prepared by RF-sputtering on quartz and PET substrates

A novel ZnO nanostructure based hydrogen H2 gas sensor operated at room temperature (25 °C) was successfully fabricated on polyethylene telephthalate (PET) substrate by RF-magnetron sputtering. Quartz substrate was used to study the effect of the substrate on the structural, optical, and sensing properties of the ZnO nanostructure. The structural, morphological, surface roughness, and optical properties of the active sensing layer were characterized by X-ray diffraction (XRD), field emission-scan electron microscopy (FE-SEM), atomic force microscopy (AFM), and UV–vis spectroscopy measurements, respectively. The ZnO nanostructure deposited on quartz substrate showed a stronger orientation of the crystallites belong (0 0 2) phase compared with that deposited on PET substrate. The sensor response was tested for hydrogen concentrations ranges from 100 ppm to 1000 ppm at operating temperatures ranging from RT to 250 °C. The sensitivity of the ZnO nanostructure based on PET substrate was approximately 24.8% and 99.53% at RT and 200 °C, respectively. On the other hand, the sensitivity of the ZnO nanostructure based on quartz substrate for 200 ppm of hydrogen at 100 °C was 96.29%. The sensors showed stability and repeatability for over 100 min. The results demonstrated the potential application of ZnO nanostructure for fabricating low-cost, lightweight, mechanically flexible, well adherent, and high-performance gas sensors.