Integration of VLS-Grown WO₃ Nanowires into Sensing Devices for the Detection of H₂S and O₃

Abstract

The inspiration behind this research is the development of tungsten oxide (WO3) nanowires based, highly sensitive and selective sensing devices directly on the active sensing platform. WO3 one-dimensional nanowires were synthesized via the vapour-phase growth technique. This approach allows the production of well-aligned and uniform nanowires on alumina substrates with their diameter and length in the nanometer range. The morphological and structural properties of nanowires have been investigated by means of the field effect electron microscopy, grazing incidence X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Finally, the fabricated WO3 nanowire sensing devices and their gas sensing performance were investigated in the presence of different oxidizing and reducing gases (especially environmental gases) at different temperatures. The WO3 sensors demonstrate high performance toward H2S and O3 at the optimal working temperatures of 400 and 200 °C, respectively, with the detection limit in the ppb level.

SAM Functionalized ZnO Nanowires for Selective Acetone Detection: Optimized Surface Specific Interaction Using APTMS and GLYMO Monolayers

“…This is the typical behavior of an n‐type semiconductor interacting with reducing gases. [ 29 ] Interestingly, the baseline conductance of bare ZnO NW sensors decreases after the functionalization with APTMS and GLYMO.…”

“…A fixed voltage of 1 V was applied to the sensors (Agilent E3631A power supply), measuring at the same time the conductance of each sensor using pico‐ammeters (Keithley 486). The response was determined by the conductance variation using the following formulae, [ 29 ]…”

1D Titanium Dioxide: Achievements in Chemical Sensing

“…Environmentally hazardous oxidizing compounds such as NO 2 , O 3 and CO 2 , etc. are among the major concerns for the human life and health [ 11 , 90 , 91 , 92 , 93 ]. For example, NO 2 is a typical air pollutant byproduct of combustion facilities, aircrafts and automobiles.…”

“…Among the different nanostructures’ forms, one-dimensional (1D) nanostructures such as nanowires exhibit unique properties such as high surface to volume ratio, high crystallinity and controlled electrical properties which make them interesting for chemical sensing applications [ 3 , 9 , 10 , 11 , 12 ]. Because there is no requirement of preliminary gas diffusion to the surface, 1D MOX gas sensors showed faster response dynamics.…”

“…Recently, MOXs such as zinc oxide (ZnO) [ 14 ], nickel oxide (NiO) [ 15 ], titanium dioxide (TiO 2 ) [ 12 ] and tungsten oxide (WO 3 ) [ 11 ] have been grown in the form of 1D nanostructures and were used for the detection of different gas analytes. Among these MOXs, TiO 2 is one of the most versatile ones and is widely used for many different applications, including photocatalysis [ 16 ], sensors [ 17 , 18 ] and photovoltaic applications [ 19 ].…”