Sensors & Transducers



Vol. 250, Issue 3, March 2021, pp. 18-25





1 Paramita Chowdhury, 2, * Sunipa Roy, 2 Nabaneeta Banerjee, 3 Swapan Das and 4 Utpal Biswas



1 Department of Electronics & Communication Engineering, Netaji Subhash Engineering College, Kolkata-700152, India

2 Department of Electronics & Communication Engineering, Guru Nanak Institute of Technology, Kolkata-700114, India

3 IC Design and Fabrication Center, Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata 700032, India

4 Department of Computer Science & Engineering, University of Kalyani, Nadia-741235, India

Tel.: 9830751850

E-mail: sunipa_4@yahoo.co.in



Received: 4 February 2021 /Accepted: 17 March 2021 /Published: 31 March 2021





Abstract: Zinc oxide (ZnO) hierarchical Nanofoam structure on ZnO nanofibers grown SiO 2 coated p-Si substrate were successfully constructed under chemical deposition technique by forming a homogeneous solution of Sodium Zincate (Na 2 ZnO 2 ) in Teflon-lined Autoclave at 120 o C. The seed layer of hierarchical ZnO nanostructure was formed by Sol-gel technique followed by CBD (Chemical bath deposition) technique to grow ZnO nanofibers. The surface morphology and crystallinity of the thin film was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) and controlled by adjusting the pH of the reaction solution. The hierarchical ZnO Nanostructure based Formaldehyde (HCHO) Sensor was tested in the resistive mode at dynamic range of 190 ppm to 2020 ppm formaldehyde vapour to defeat sick building syndrome. It was found to offer high response magnitude 94.8 % at 2020 ppm at very low optimum operating temperature 100 o C with fast response time (20 s). Finally, the possible mechanism of decomposition of formaldehyde sensor has been discussed with detailed explanation of higher response magnitude on exposure of formaldehyde vapour with energy band diagram.


Keywords: ZnO hierarchical nanostructure, ZnO nanofibers, Teflon-lined Autoclave, Formaldehyde sensor, Sensing mechanism, Energy band diagram.

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