High performance hydrogen sensor based on Mn implanted ZnO nanowires array fabricated on ITO substrate

- Novel hydrogen sensor based on Mn implanted ZnO nanowires was fabricated on ITO substrate by spray pyrolysis.
- Reduction in crystallite size and porous worm-like morphology was recorded for 4 wt.% ZnO:Mn.
- PL emission and optical absorption studies revealed tunable band gap of ZnO with Mn doping.
- Mn implanted ZnO sensor revealed high sensitivity towards H2 at room temperature.

In the present research, we propose a novel approach for the detection of hydrogen gas using Mn implanted ZnO nanowires fabricated onto ITO coated glass substrate by chemical spray pyrolysis deposition. The effect of Mn concentration on the structural, optical and morphological properties of ZnO films were investigated. X-ray diffraction studies showed that the Mn implanted ZnO films were grown as a polycrystalline hexagonal wurtzite phase without any impurities. The (101) peak position of ZnO-Mn films was shifted towards a lower angle with increasing Mn concentration. The optical band gap decreased from 3.45 eV to 3.23 eV with increasing Mn content. PL spectra, revealed sharp and strong near band edge emission which suggests that ZnO nanowires exhibit high crystalline quality. FE-SEM images of Mn implanted ZnO show perfectly aligned nanowires for all the films fabricated on ITO. The material (Zn, O, Mn) was confirmed by EDX spectra. The hydrogen sensing mechanism of the Mn implanted ZnO nanowire sensor was also discussed. It was found that H2 response was significantly enhanced by more than one order of magnitude with increasing Mn doping concentrations. The studied ZnO-Mn films coated on ITO substrate can be used as a low cost and easy-fabrication hydrogen sensing material.

Reaction of hydrogen molecules with the adsorbed oxygen species.147