Journal of Sol-Gel Science and Technology

, Volume 88, Issue 2, pp 322–333 | Cite as

Sol–gel spin coating assisted room temperature operated nanostructured ZnO ethanol sensor with behavior transformation

  • Ajay BeniwalEmail author
  • Praveen Kumar Sahu
  • Sunny Sharma
Original Paper: Devices based on sol-gel or hybrid materials


In this paper, zinc oxide (ZnO) thin film sensor has been fabricated using different sol–gel spin coating route to detect very low concentration (2 ppm) of ethanol vapors at room temperature (RT). The sensor shows appreciable response ~60% for 100 ppm of ethanol (C2H5OH) vapors at RT under humidity level ~55% RH. Various sensing parameters viz. % response, selectivity, stability, response/recovery time, repeatability, and reproducibility have been studied successfully. Structural and morphological properties have been studied via X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD reveals the wurtzite structure of polycrystalline ZnO thin film. AFM, SEM, and TEM results confirm the wavy structure of well-shaped and slackly distributed ZnO nanograins with average particle size in range ~15–25 nm. The analyte sensing properties at room temperature can be ascribed to higher specific surface area due to nanograins formation. The significant effect of operating temperature on sensor’s performance is also analysed in order to obtain the optimum temperature (Topt) of the sensor device. Response reaches to 321.7% for 100 ppm of ethanol vapors at Topt (175 °C). The transformation in the behavior of sensing layer is observed which is described on the basis of experimental studies.


  • Growth of nanostructured ZnO thin film sensor for ethanol detection using facile sol-gel spin coating technique.

  • XRD, TEM, AFM and SEM are used for structural, topography and morphological properties analysis of the synthesized ZnO layer.

  • Good sensitivity, selectivity, reproducibility and high stability observed towards ethanol detection at room temperature. Sensitivity is found to be improved multifold at higher temperatures.

  • The transformation in the behavior of sensing layer is observed and explained on the basis of reducing and oxidizing byproducts formation upon ethanol exposure.


Sol–gel Nanograins Ethanol Room temperature % Response Sensing behavior transformation 



The research work is sponsored by Indian Institute of Information Technology – Allahabad, under seed money research grant with file no. - GRN - IIIT-A/DR(F&A)/Seed Money/2017/Int.85. The authors’ are grateful to Central Instrument Facility Centre (CIFC) - IIT (BHU), Varanasi for the technical support of the structural characterization.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Electronics & Communication EngineeringIndian Institute of Information TechnologyAllahabadIndia
  2. 2.Department of Electronics EngineeringIndian Institute of Technology (Banaras Hindu University)VaranasiIndia

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