Humidity sensing enhancement through n-/p-type CdO-CrO heterostructures for eco-friendly monitoring systems

Semiconductor metal oxides have garnered significant attention for humidity sensing applications due to their facile fabrication, cost-effectiveness, environmental compatibility, and chemical stability. In this study, CrO was prepared via sol-gel route, CdO metal oxide prepared via co-precipitation...

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Bibliographic Details
Main Authors: Adil Rauf, Rizwan Akram, Ayesha Masood, Zahid Imran, Safia Hassan, Shumaila Karamat
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S259012302502643X
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Summary:Semiconductor metal oxides have garnered significant attention for humidity sensing applications due to their facile fabrication, cost-effectiveness, environmental compatibility, and chemical stability. In this study, CrO was prepared via sol-gel route, CdO metal oxide prepared via co-precipitation method, and finally the composite of CdO-CrO was achieved by mixing both the materials in mortar and pestle. The structural analysis was done for all the three samples using X-ray Diffraction (XRD) which confirms the successful formation of CdO and CrO and CdO-CrO composite material. Using Scherrer formula the crystallite sizes were also estimated i.e. ∼56 nm for CdO, ∼35 nm for CrO and ∼46 nm for CdO-CrO composite. Scanning Electron Microscopy (SEM) revealed the intricate morphology of the synthesized material, while Energy Dispersive X-ray Spectroscopy (EDX) verified its elemental purity. The humidity sensing performance was investigated across a relative humidity range of 11 % – 97 % using impedance spectroscopy in the frequency range of 20 Hz to 1 MHz. A dedicated %RH sensor was fabricated by depositing the CdO-CrO composite material onto copper electrodes using drop casting method, demonstrating an impressive response and recovery time of ∼9 sec and ∼7 sec, respectively, with minimal hysteresis ∼8 % and high sensitivity (0.12 MΩ/%RH). These results underscore the potential of CdO-CrO composite-based sensors as highly sensitive, rapid, and reliable candidates for practical humidity sensing applications.
ISSN:2590-1230