Shivaji University

About: Shivaji University is a education organization based out in Kolhāpur, Maharashtra, India. It is known for research contribution in the topics: Thin film & Scanning electron microscope. The organization has 3078 authors who have published 5295 publications receiving 115397 citations.

Fabrication of nanostructured ZnO thin films based NO2 gas sensor via SILAR technique

Abstract: Zinc oxide (ZnO) thin films have been widely used as an effective gas sensor element. In the present study, nanostructured thin films of ZnO were prepared by using the simplistic and economical successive ion layer adsorption and reaction (SILAR) technique. The effects of SILAR cycles on the structural, optical, surface morphological and electrical properties of nanostructured ZnO thin films were investigated. Characterization techniques such as XRD, UV-vis, PL, FESEM, and Hall measurement were utilized to study the physical and chemical properties of the synthesized films. XRD confirms the formation of hexagonal phase structural ZnO thin films. FE-SEM analysis reveals the formation of well-dispersed ZnO nanoparticles having sizes of ∼18–40 nm. The SILAR cycles play a key role in the synthesis of nanostructured ZnO thin films and it is found that, with increasing SILAR cycles, the grain size continues increasing. Optical studies confirm the presence of oxygen vacancies in synthesized ZnO thin films. Finally, the ZnO thin films were exposed to NO 2 gas with a concentration of 100 ppb–200 ppm and the resulting resistance transient was recorded. The nanostructured ZnO thin films synthesized at 30 SILAR cycles displays an enhancement of gas sensing performance and exhibit significantly higher responses (∼5% per ppm). Moreover, our ZnO thin-film-based gas sensor is sensitive to very low concentrations of dangerous NO 2 (100 ppb). The sensitive gas sensor used to trace level NO 2 detection, synthesized via simple SILAR route proves the novelty of our work. The present report provides a new direction in fabricating nanostructured ZnO thin films for low-cost and efficient gas sensing applications.