Growth-Temperature Dependent Unpassivated Oxygen Bonds Determine the Gas Sensing Abilities of Chemical Vapor Deposition-Grown CuO Thin Films

Nanda, A and Singh, V and Jha, RK and Sinha, J and Avasthi, S and Bhat, N (2021) Growth-Temperature Dependent Unpassivated Oxygen Bonds Determine the Gas Sensing Abilities of Chemical Vapor Deposition-Grown CuO Thin Films. In: ACS Applied Materials and Interfaces, 13 (18). pp. 21936-21943.

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Abstract

CuO is a multifunctional metal oxide excellent for chemiresistive gas sensors. In this work, we report CuO-based NO2 sensors fabricated via chemical vapor deposition (CVD). CVD allows great control on composition, stoichiometry, impurity, roughness, and grain size of films. This endows sensors with high selectivity, responsivity, sensitivity, and repeatability, low hysteresis, and quick recovery. All these are achieved without the need of expensive and unscalable nanostructures, or heterojunctions, with a technologically mature CVD. Films deposited at very low temperatures (�350 °C) are sensitive but slow due to traps and small grains. Films deposited at high temperatures (�550 °C) are not hysteretic but suffer from low sensitivity and slow response due to lack of surface states. Films deposited at optimum temperatures (350-450 °C) combine the best aspects of both regimes to yield NO2 sensors with a response of 300 at 5 ppm, sensitivity limit of 300 ppb, hysteresis of <20, repeatable performance, and recovery time of �1 min. The work demonstrates that CVD might be a more effective way to deposit oxide films for gas sensors. ©

Item Type:	Journal Article
Publication:	ACS Applied Materials and Interfaces
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Copper oxides; Gas detectors; Gas sensing electrodes; Heterojunctions; Hysteresis; Metals; Nitrogen oxides; Oxide films; Oxygen; Thin films, Chemical vapor depositions (CVD); High selectivity; High temperature; Multifunctional metal oxide; Optimum temperature; Sensitivity limit; Temperature dependent; Very low temperatures, Chemical vapor deposition
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	16 Aug 2021 07:50
Last Modified:	16 Aug 2021 07:50
URI:	http://eprints.iisc.ac.in/id/eprint/69197

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