Oxygen Partial Pressure Effect on Nano-Structure and NO Gas Detection Sensitivity of Sputtered MoO₃ Thin Films

Abstract:

This paper explains the influence of oxygen partial pressure on crystallographic structure, surface morphology and sensing properties of sputtered MoO₃ thin films. The MoO₃ thin films were deposited by DC reactive magnetron sputtering technique on glass substrate at different oxygen partial pressures in the range of 5×10^-5-4×10^-4 mbar. X-ray diffraction (XRD) results showed that all prepared films were polycrystalline of α-MoO₃ stable orthorhombic phase. Atomic force microscopy (AFM) images depicted a needle-like structure for deposited film at lowest oxygen partial pressure (5×10^-5 mbar) and a granular structure for formed samples at higher oxygen partial pressures (1×10^-4 and 2×10^-4 mbar). These results also showed that increasing of oxygen partial pressure up to 2×10^-4 mbar caused increasing of grains size and surface roughness, while an increase in oxygen partial pressure to the highest pressure (4×10^-4 mbar) had an inverse effect. The electrical response of samples was measured in vacuum and NO environments in the temperature range of 150-350 K. This study showed that the NO gas detection sensitivity of MoO₃ thin films improved with increasing of oxygen partial pressure up to 2×10^-4 mbar, and then decreased.

• Periodical: Applied Mechanics and Materials (Volumes 446-447)
• Pages: 185-190
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.446-447.185
• Online since: November 2013
• Authors: Kaykhosrow Khojier, Mahsa Fasihnikoutalab, Ghazal Moradi
• Keywords: Crystallographic Structure, MoO₃, Sensing Properties, Surface Morphology, Thin Film

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