Title: MoO₃:In₂O₃ binary oxide thin films as CO gas sensor

Authors: Nimba B. Kothawade; Vikas V. Deshmane; Arun V. Patil

Addresses: Department of Physics, Arts, Science and Commerce College, Kalwan, Nashik, Maharashtra, 423501, India ' Department of Physics, SICES Degree College, Ambarnath, Thane, Maharashtra, 422505, India ' Department of Physics, Arts, Science and Commerce College, Surgana, Nashik, Maharashtra, 422211, India

Abstract: The aim of the study was to understand gas sensing properties of thin films of molybdenum trioxide and indium oxide (MoO₃-In₂O₃) indifferent normality proportions. Thin films were prepared by spray pyrolysis technique on glass substrates at 400°C. The films were characterised using X-ray diffraction, scanning electron microscope and energy dispersive analysis by X-ray spectra. The electrical and gas sensing properties of the films were studied using static gas sensing apparatus. The resistivity of films increased by adding MoO₃ as the dopant in In₂O₃. The maximum resistivity of film was found 1.75 × 10⁴ Ωm for 0.3N (MoO₃) and 0.1N (In₂O₃) binary oxide films. The films were tested against five different target gases. The composition ratio 0.3N:0.1N films showed the 70.50% sensitivity for 300 ppm CO gas at 150°C. The response time (15s) and recovery time (25s) was found to be quick.

Keywords: molybdenum trioxide; indium oxide; spray pyrolysis; carbon monoxide gas sensor; binary oxides; XRD; X-ray diffraction; SEM; scanning electron microscopy; activation energy.

DOI: 10.1504/IJMMP.2020.110525

International Journal of Microstructure and Materials Properties, 2020 Vol.15 No.3, pp.229 - 241

Received: 09 Apr 2020
Accepted: 15 May 2020
Published online: 22 Oct 2020 *

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