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© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

In this study we report the specific interaction of various gases on the modified surface of acoustic wave devices for gas sensor applications, using the piezoelectric ceramic material BaSrTiO3 (BST), with different concentrations of Sr. For enhancing the sensitivity of the sensor, the conductive polymer polyethylenimine (PEI) was deposited on top of BST thin films. Thin films of BST were deposited by pulsed laser deposition (PLD) technique and integrated into a test heterostructure with PEI thin films deposited by matrix assisted pulsed laser evaporation (MAPLE) and interdigital Au electrodes (IDT). Further on, the layered heterostructures were incorporated into surface acoustic wave (SAW) devices, in order to measure the frequency response to various gases (N2, CO2 and O2). The frequency responses of the sensors based on thin films of the piezoelectric material deposited at different pressures were compared with layered structures of PEI/BST, in order to observe differences in the frequency shifts between sensors. The SAW tests performed at room temperature revealed different results based on deposition condition (pressure of oxygen and the percent of strontium in BatiO3 structure). Frequency shift responses were obtained for all the tested sensors in the case of a concentration of Sr x = 0.75, for all the analysed gases. The best frequency shifts among all sensors studied was obtained in the case of BST50 polymer sensor for CO2 detection.

Details

Title
Laser Processed Hybrid Lead-Free Thin Films for SAW Sensors
Author
Enea, Nicoleta 1 ; Valentin Ion 2   VIAFID ORCID Logo  ; Viespe, Cristian 2   VIAFID ORCID Logo  ; Constantinoiu, Izabela 2   VIAFID ORCID Logo  ; Buiu, Octavian 3   VIAFID ORCID Logo  ; Romanitan, Cosmin 3 ; Scarisoreanu, Nicu Doinel 2 

 National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Romania; Department of Physics and Astronomy, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino, FI, Italy; Faculty of Physics, University of Bucharest, 077125 Magurele, Romania 
 National Institute for Laser, Plasma and Radiation Physics, 077125 Magurele, Romania 
 National Institute for Research and Development in Microtechnologies, 077190 Voluntari, Romania 
First page
8452
Publication year
2022
Publication date
2022
Publisher
MDPI AG
e-ISSN
19961944
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2748556452
Copyright
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.