RF Sputtered CeO2 Thin Films-Based Oxygen Sensors

Ramshanker, N and Ganapathi, Kolla Lakshmi and Bhat, M S and Mohan, S (2019) RF Sputtered CeO2 Thin Films-Based Oxygen Sensors. In: IEEE SENSORS JOURNAL, 19 (22). pp. 10821-10828.

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Abstract

In this paper, we report the scalable, high sensitivity, fast response, and low operating temperature Cerium oxide (CeO2) thin film-based oxygen sensors by optimizing CeO2 film thickness. CeO2 thin films of thickness ranging from 90 to 340 nm have been deposited at 400 degrees C using radio frequency (RF) magnetron sputtering on Al2O3 substrates. Ellipsometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize the CeO2 films for their thickness, structural, compositional/chemical, and surface morphology properties. Gas sensors have been fabricated using CeO2 film as a sensing material and tested in an oxygen gas environment. CeO2 film with an optimum thickness of 260 nm has shown high sensitivity (12.6) and fast response time (<= 10 s) along with fast recovery time (15 s) at a low operating temperature of 400 degrees C. To the best of our knowledge, these are the best values reported till date for undoped CeO2 thin film-based oxygen sensors. Furthermore, from the sensor's response, it was observed that there was no drifting from the baseline. This superior performance of CeO2 thin film-based oxygen sensor may be attributed to the combination of three factors, i.e., 1) high surface energy and reactivity due to the presence of (200) oriented CeO2 plane; 2) low resistance due to better crystallinity; and 3) perfect stoichiometry with required roughness.

Item Type:	Journal Article
Publication:	IEEE SENSORS JOURNAL
Publisher:	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Additional Information:	Copyright of this article belongs to IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Keywords:	Cerium oxide (CeO2); RF sputtering; thickness optimization; thin film oxygen sensor; high sensitivity; fast response time
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	16 Jan 2020 11:30
Last Modified:	16 Jan 2020 11:30
URI:	http://eprints.iisc.ac.in/id/eprint/64346

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