Comparison of the Sensing Properties of ZnO Nanowalls-Based Sensors toward Low Concentrations of CO and NO2

Abstract

This work focuses on the synthesis and gas sensing properties of ZnO nanowalls (ZnO NWLs) grown by a simple cheap chemical bath deposition method on a thin layer of aluminum (about 20 nm thick) printed on the Pt interdigitated electrodes area of conductometric alumina platforms. Post-deposition annealing in nitrogen atmosphere at 300 • C enabled the formation of a ZnO intertwined 2D foils network. A wide characterization was carried out to investigate the composition, morphology and microstructure of the nanowalls layer formed. The gas sensing properties of the films were studied by measuring the changes of electrical resistance upon exposure to low concentrations of carbon monoxide (CO) and nitrogen dioxide (NO 2 ) in air. The sensor response to CO or NO 2 was found to be strongly dependent on the operating temperature, providing a means to tailor the sensitivity and selectivity toward these selected target gases.

Designing zinc oxide nanostructures (nanoworms, nanoflowers, nanowalls, and nanorods) by pulsed laser ablation technique for gas‐sensing application

“…The hierarchical architecture feature of the nest‐like structure (nanowall) has a very promising sensor application due to its very high surface‐to‐volume ratio; thus a high surface area for gas diffusion and therefore expected to have a good electrical response for sensor applications . The gas‐sensing capability of a good sensor is largely affected by the particle size and surface morphology.…”

“…Seed layer affects the quality of the grown nanostructure and could also improve adhesion of the nanostructures to the substrate which is very important for materials designed for sensor applications . A seed layer is grown on the substrate at T L = 300°C for 2 minutes at 10 mTorr prior to the growth of ZnO nanoworms, nanowalls, and nanorods at (temperature, pressure) values of (550°C and 2 Torr), (550°C and 0.5 Torr), and (650°C and 2 Torr), respectively.…”

“…However, in gas‐sensing application, the gas sensor base materials require nanostructures with large surface‐to‐volume ratio and good porosity with high diffusivity and active areas . Coupled with its unique properties which are ideal for sensor, ZnO nanowall structures are one of the good candidates for this purpose .…”

Novel 2D-Inorganic Materials for Gas Sensing

“…An original work was presented by Dr. Bruno, focused on the synthesis and gas sensing properties of ZnO nanowalls (ZnO NWLs) grown by a simple, inexpensive chemical bath deposition method on a thin layer of aluminum (about 20 nm thick) printed on the Pt interdigitated electrode area of conductometric alumina platforms [8]. Post-deposition annealing in nitrogen atmosphere at 300 • C enabled the formation of a ZnO intertwined 2D foil network.…”

ZnO Microflowers Grown by Chemical Bath Deposition: A Low-Cost Approach for Massive Production of Functional Nanostructures

“…A shining example of the development of CBD is the wide variety of zinc oxide (ZnO) nanostructures achievable via this method, spanning from nanorods to nanowalls, from nanotubes to nanoplates [8,10,[12][13][14][15]. In the last 20 years, a remarkable interest has been generated by ZnO nanostructures [16,17] because of the unique combination of material properties and nanotechnology, enabling a variety of applications, as in sensors and in electro-optical devices [17][18][19][20][21][22].…”