Studies on resistive-type humidity sensing properties of copper-zinc mixed metal oxide nanostructures

• Published in: Inorganic chemistry communications 2023-07, Vol.153, p.110824, Article 110824
• Main Authors: Pathan, Abbas S., Gapale, Deepak L., Bhosale, Shivaji V., Landge, Abhijit S., Jadkar, Sandesh R., Arote, Sandeep A
• Format: Article
• Language: English
• Subjects: CuO; Humidity Sensor; Nanostructured thin films; Nebulizer assisted spray pyrolysis technique; Sensitivity; ZnO
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2023.110824

[Display omitted] •Synthesis of CuO-ZnO nanostructure thin films deposited by in-situ low cost nebulized assisted spray pyrolysis system.•The CuO-ZnO concentration in the nanostructures shows a significant effect on the structural, optical, and morphological properties of the synthesized samples.•Effect of crystallite size and surface morphology on humidity sensing performance is discussed. The present work reports the synthesis of CuO-ZnO nanostructured thin films by in-situ low-cost nebulized assisted spray pyrolysis system. The physicochemical properties of the prepared samples were measured using various characterization techniques. X-Ray Diffraction (XRD) studies confirmed the formation of crystalline CuO-ZnO nanostructures and revealed hexagonal wurtzite-type crystal structure. The appearance of CuO-ZnO nanostructures was also confirmed using Fourier Transform Infrared Spectroscopy (FTIR). Optical characterization showed that optical reflection of CuO-ZnO initially increased with increase in CuO in the sample and then decreased. The same trend was observed for band gap energy values which varied from 3.87 eV to 4.01 eV with change in molar ratio of CuO and ZnO in the sample. SEM analysis revealed the change in morphology of CuO-ZnO nanostructures with change in molar ratio of CuO and ZnO in the composite. Further, the humidity sensing behavior of the prepared nanostructured thin films was investigated in the range of 30 % to 90% relative humidity. The results obtained showed that the resistance of the prepared films decreased with increasing relative humidity (RH). The nanostructure with CuO (60%) − ZnO (40%) exhibited superior humidity sensing performance which was stable with sensitivity of about 2.33 MΩ/%RH (at 57 % RH); and response-recovery time of 29 s and 16 s respectively.