Room-temperature acetaldehyde-sensing properties of SILAR-deposited ZnO thin films: role of tungsten doping

The demand for the development of chemiresistive sensors for the detection of acetaldehyde has been rapidly increasing, as its concentration needs to be continuously monitored in many industries. Also, exposure to acetaldehyde beyond a permissible limit leads to various health complications including nausea, irritation, headache, and respiratory tract complications. In this context, acetaldehyde-sensing properties of tungsten-doped ZnO thin films deposited using the Successive Ionic Layer Adsorption and Reaction (SILAR) technique by varying the tungsten-dopant concentration from 2 to 10 mM are reported. XRD patterns of both the undoped and tungsten-doped ZnO films divulge the formation of hexagonal wurtzite structure with a preferential plane orientation of (0 0 2). Formation of clustered tiny nanobeads composed of spherical nanograins was observed for undoped ZnO thin film, and the formation of spherical nanoaggregates with dimensions less than similar to 1 mu m was observed for the films deposited with tungsten concentrations of 2-8 mM. At 10 mM, formation of homogeneously distributed elongated nanobead-like morphology was observed. Room-temperature vapor-sensing properties of undoped and W-doped ZnO thin films were investigated. Undoped ZnO thin film was selective towards ammonia, whereas the doped ZnO thin films showed a better response towards acetaldehyde. In particular, the film deposited at 10 mM W-doped ZnO exhibited a sensing response of 947 towards 100 ppm of acetaldehyde. The response and recovery times were found to be 53 and 5 s, respectively, with a minimum detection limit of 10 ppm.

Automated summary

This study reports the acetaldehyde-sensing properties of tungsten-doped ZnO thin films deposited using the SILAR technique, showing that tungsten doping enhances the response to acetaldehyde, particularly with the 10 mM tungsten-doped ZnO thin film exhibiting a response of 947 to 100 ppm acetaldehyde.