Synthesis of ZnO comb-like nanostructures for high sensitivity $$\hbox {H}_{2}$$S gas sensor fabrication at room temperature

Zinc oxide (ZnO) comb-like nanostructures were successfully synthesized on the silicon substrate without a catalyst via chemical vapour deposition. The morphology and crystal structure of the product were characterized by scanning electron microscope and X-ray diffractometer. In this research, a simple gas sensor was fabricated based on the principle of change in resistivity due to oxygen vacancies, which makes its surface chemically and electrically active. The fabricated ZnO nanostructures proved to be quite sensitive to low concentration of \(\hbox {H}_{2}\hbox {S}\) gas at room temperature. The sensitivity and response time were measured as a function of gas concentrations. Small response time (48–22 s) and long recovery time (540 s) were found at \(\hbox {H}_{2}\hbox {S}\) gas concentrations of 0.1–4 ppm, respectively. ZnO comb-like structures are considered as the most suitable materials for gas sensor fabrication due to their high sensing properties. These nanostructures growth and \(\hbox {H}_{2}\hbox {S}\) gas sensing mechanism were also discussed.