Fabrication of Fe-doped WO3 films for NO2 sensing at lower operating temperature

SENSORS AND ACTUATORS B-CHEMICAL

卷:221

Article

Tesfamichael, T.¹  Piloto, C.¹  Arita, M.²  Bell, J.¹ 

[1] Queensland Univ Technol, Fac Sci & Engn, Brisbane, Qld 4000, Australia

[2] Hokkaido Univ, Lab Nanosci & Mat, Kita Ku, Sapporo, Hokkaido 0600814, Japan

关键词: Nanostructure thin films;    Tungsten oxide;    Fe-doping;    Optical band gap;    NO2 gas sensing;    Low operating temperature;   

DOI  :  10.1016/j.snb.2015.06.090

来源: Elsevier

【 摘 要 】

Fe-doped tungsten oxide thin films with different concentrations (0-2.6 at%) were synthesized on glass and alumina substrates at room temperature using DC reactive sputtering and subsequently annealed at 300 degrees C for 1 h in air. The alumina substrate has pre-printed interdigitated Pt-electrodes for gas sensing measurements. The effects of Fe-doping on the film structure and morphology, electronic and optical properties for gas sensing were investigated. The grain size of the different films on the alumina and Pt regions of the substrate vary only slightly between 43 and 57 nm with median size of about 50 nm. Raman spectra showed that the integrated intensity of W=O to O-W-O bands increases with increasing Fe concentrations and this indicated an increase in the number of defects. From XPS the different concentrations of the Fe-doped films were 0.03 at%, 1.33 at% and 2.6 at%. All the films deposited on glass substrate have shown similar visible transmittance (about 70%) but the optical band gap of the pure film decreased form 3.30 eV to 3.15 eV after doping with 2.6 at% Fe. The Fe-doped WO3 film with the highest Fe concentration (2.6 at% Fe) has shown an enhanced gas sensing properties to NO2 at relatively lower operating temperature (150 degrees C) and this can be attributed to the decrease in the optical band gap and an increase in the number of defects compared to the pure WO3 film. (C) 2015 Elsevier B.V. All rights reserved.

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