Abstract
Molybdenum trioxide (MoO3) nanobelts have been deposited onto the glass substrates using chemical spray pyrolysis (CSP) deposition method. The XRD patterns reveal that films are polycrystalline having an orthorhombic crystal structure. Raman spectra confirm that the films are orthorhombic in phase. The XPS study shows the presence of two well resolved spectral lines of Mo-3d core levels appearing at the binding energy values of 232.82eV and 235.95eV corresponding to Mo-3d5/2 and Mo-3d3/2, respectively. These binding energy values are assigned to Mo6+ oxidation state of fully oxidized MoO3. The FE-SEM micrographs show the formation of nanobelts-like morphology. The AFM micrographs reveal that the RMS surface roughness increases from 16.5nm to 17.5nm with increase in film thickness from 470nm to 612nm and then decreases to 16nm for 633nm film thickness. The band gap energy is found to be decreased from 3.40eV to 3.38eV. To understand the electronic transport phenomenon in MoO3 thin films, dielectric properties are studied. For 612nm film thickness, the highest NO2 gas response of 68% is obtained at an operating temperature of 200°C for 100ppm concentration with response and recovery times of 15s and 150s, respectively. The lower detection limit is found to be 10ppm which is half of the immediately dangerous to life or health (IDLH) value of 20ppm. Finally, NO2 gas sensing mechanism in an orthorhombic MoO3 crystal structure is discussed in detail.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have