Investigation of Rapid Gas-Sensitive Properties Degradation of ZnO–SnO2 Thin Films Grown on the Glass Substrate

Victor V Petrov,Maria G Volkova,Soslan A Khubezhov,Ekaterina M Bayan,Yuri N Varzarev

doi:10.3390/chemosensors8020040

Victor V Petrov, Maria G Volkova + Show 3 more

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https://doi.org/10.3390/chemosensors8020040

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Abstract

ZnO–SnO2 films with a thickness of up to 120 nm have been prepared on glass substrates by pyrolysis at 550 °C of three spin-coated organic precursors films. Films of four compositions were obtained on glass substrates. The prepared films were characterized by SEM, XRD, and XPS analysis. Electrophysical studies have shown that the activation energy of the temperature conductivity for all films is equal to 0.75 eV. While the gas-sensitive characteristics by CO treatment in low concentrations at a temperature of 200–300 °C was studied, their rapid degradation was found. Studies using the XPS method have shown that ZnO–SnO2 films contain sodium, which is diffused from the soda-lime glass substrate during the film formation. Studies of XPS spectra after CO treatment have shown that the film surface is almost 50% composed of adsorbed water molecules and OH groups. OH groups are part of the sodium, tin, and zinc hydroxides formed on the surface. In addition, zinc hydrocarbonates are formed on the surface of the films. The detected insoluble compounds lead to the degradation of gas-sensitive properties of ZnO–SnO2 films.

Highlights

Creating of gas-sensitive sensors for detecting environmentally hazardous gases based on nanoscale film materials is an important task for most researchers due to increased atmospheric pollution
The most widespread materials for gas-sensitive-resistive sensors are semiconductor metal oxides obtained in the film form, such as SnO2 [5], ZnO [6], In2 O3 [7], WO3 [8], and others [9,10] due to their special properties, such as stability to the environment, high sensitivity, etc
There are frequent cases of using nanocomposite materials based on the abovementioned oxides, among which tin dioxide plays important role due to its high sensitivity to different hazardous gases [11]

Summary

Introduction

Creating of gas-sensitive sensors for detecting environmentally hazardous gases based on nanoscale film materials is an important task for most researchers due to increased atmospheric pollution. Research work in this direction has been actively carried out over the past 20 years [1,2], and it has been established that the sensitivity of gas-sensitive sensors is affected by both the nature of the nanomaterial and its structure [3,4]. There are frequent cases of using nanocomposite materials based on the abovementioned oxides, among which tin dioxide plays important role due to its high sensitivity to different hazardous gases [11]. It was shown that sensors based on Chemosensors 2020, 8, 40; doi:10.3390/chemosensors8020040 www.mdpi.com/journal/chemosensors

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