Theoretical analysis of acoustoelectrical sensitivity in SAW gas sensors with single and bi-layer structures

Jakubik, W.; Powroźnik, Paulina; Wrotniak, J. A.; Krzywiecki, Maciej

doi:10.1016/j.snb.2016.05.157

Cited by 18 publications

(15 citation statements)

References 13 publications

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“…It is well known that surface acoustic wave propagation is very sensitive to changes in electrical conductivity through acoustoelectric interactions [21]. Acousto-electrical interactions between the electrical potential accompanying SAW propagation and mobile charges in the sensing film can be enhanced in bilayers [12,17].…”

Section: Discussionmentioning

confidence: 99%

Surface Acoustic Wave Hydrogen Sensors Based on Nanostructured Pd/WO3 Bilayers

Miu

Bı̂rjega

Viespe

2018

Sensors

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The effect of nanostructure of PLD (Pulsed Laser Deposition)-deposited Pd/WO3 sensing films on room temperature (RT) hydrogen sensing properties of SAW (Surface Acoustic Wave) sensors was studied. WO3 thin films with different morphologies and crystalline structures were obtained for different substrate temperatures and oxygen deposition pressures. Nanoporous films are obtained at high deposition pressures regardless of the substrate temperature. At lower pressures, high temperatures lead to WO3 c-axis nanocolumnar growth, which promotes the diffusion of hydrogen but only once H2 has been dissociated in the nanoporous Pd layer. XRD (X-ray Diffraction) analysis indicates texturing of the WO3 layer not only in the case of columnar growth but for other deposition conditions as well. However, it is only the predominantly c-axis growth that influences film sensing properties. Bilayers consisting of nanoporous Pd layers deposited on top of such WO3 layers lead to good sensing results at RT. RT sensitivities of 0.12–0.13 Hz/ppm to hydrogen are attained for nanoporous bilayer Pd/WO3 films and of 0.1 Hz/ppm for bilayer films with a nanocolumnar WO3 structure. SAW sensors based on such layers compare favorably with WO3-based hydrogen detectors, which use other sensing methods, and with SAW sensors with dense Pd/WO3 bilayers.

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Section: Discussionmentioning

confidence: 99%

Surface Acoustic Wave Hydrogen Sensors Based on Nanostructured Pd/WO3 Bilayers

Miu

Bı̂rjega

Viespe

2018

Sensors

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“…Through the acusto-electrical interactions, the surface acoustic wave is very sensitive at changes in electrical conductivity [37], and these interactions could be enhanced in bilayers [12]. The acusto-electrical effect comes from the interaction of electrical potential that accompanies the SAW propagation with the mobile charges in the sensing film [12].…”

Section: Sensor Propertiesmentioning

confidence: 99%

Development of Pd/TiO2 Porous Layers by Pulsed Laser Deposition for Surface Acoustic Wave H2 Gas Sensor

Constantinoiu

Viespe

2020

Nanomaterials

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The influence of sensitive porous films obtained by pulsed laser deposition (PLD) on the response of surface acoustic wave (SAW) sensors on hydrogen at room temperature (RT) was studied. Monolayer films of TiO 2 and bilayer films of Pd/TiO 2 were deposited on the quartz substrates of SAW sensors. By varying the oxygen and argon pressure in the PLD deposition chamber, different morphologies of the sensitive films were obtained, which were analyzed based on scanning electron microscopy (SEM) images. SAW sensors were realized with different porosity degrees, and these were tested at different hydrogen concentrations. It has been confirmed that the high porosity of the film and the bilayer structure leads to a higher frequency shift and allow the possibility to make tests at lower concentrations. Thus, the best sensor, Pd-1500/TiO 2 -600, with the deposition pressure of 600 mTorr for TiO 2 and 1500 mTorr for Pd, had a frequency shift of 1.8 kHz at 2% hydrogen concentration, a sensitivity of 0.10 Hz/ppm and a limit of detection (LOD) of 1210 ppm. SAW sensors based on such porous films allow the detection of hydrogen but also of other gases at RT, and by PLD method such sensitive porous and nanostructured films can be easily developed.

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“…As described before, this choice is based on the fact that acoustic transduction could be complementary to the optical transduction; in addition, the Love wave device, which is based on a shear horizontal (SH) wave propagating in a thin layer deposited on a piezoelectric substrate, is able to operate in aqueous media without excessive acoustic energy loss [9,17]. Thus, the sensing mechanism is essentially based on the mass effect (amount of mass deposited on the surface of the sensor) but also on the overall mechanical and electrical aqueous media properties, including in particular the density, viscosity, thickness [17][18][19], and electrical conductivity [20,21].…”

Section: Love Wave Transducermentioning

confidence: 99%

Mobile Acoustic Wave Platform Deployment in the Amazon River: Impact of the Water Sample on the Love Wave Sensor Response

Tamarin

Rube

Lachaud

et al. 2019

Sensors

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This paper presents an experimental platform allowing in situ measurement in an aqueous medium using an acoustic Love wave sensor. The aim of this platform, which includes the sensor, a test cell for electrical connections, a microfluidic chip, and a readout electronic circuit, is to realize a first estimation of water quality without transportation of water samples from the field to the laboratory as a medium-term objective. In the first step, to validate the ability of such a platform to operate in the field and in Amazonian water, an isolated and difficult-to-access location, namely, the floodplain Logo Do Curuaï in the Brazilian Amazon, was chosen. The ability of such a platform to be transported, installed on site, and used is discussed in terms of user friendliness and versatility. The response of the Love wave sensor to in situ water samples is estimated according to the physical parameters of Amazonian water. Finally, the very good quality of the acoustic response is established, potential further improvements are discussed, and the paper is concluded.The other method is based on the collection of in situ samples with conditioning methods that require not only the transport of the samples from the field to analytical laboratories but also the analysis of these same samples by highly qualified personnel using analytical chemistry tools that are sometimes very expensive, such as gas chromatographs, mass spectrometers, and electrophoretic stations.Drawbacks include the biochemical degradation of the samples during their collection and transportation [6]. Moreover, this method does not allow an exhaustive analysis of the biochemical compounds in the water column over a large area of investigation. Indeed, the logistics of deployment and the overall cost, including consumables and the workforce, result in a very low frequency of in-field sample collection and necessitate complex work to evaluate a large number of samples that nevertheless cannot be efficiently treated in terms of time compared to the surfaces to be studied. This drawback is not compatible with the need for water quality data over a large area [7].An intermediate approach, allowing the coverage of a high surface area while analyzing biochemical compounds in the water column, is to use in situ biochemical sensors that are easily deployable. If one sensor can provide information about the presence of a target compound, certain properties are important for covering a large area with a minimum cost, such as good sensitivity, easy communicating, low cost, user friendliness, and low power consumption or even passive power operation. These properties leverage autonomous sensor networks to cover a large area and/or to allow the use of nonexpert people to realize rapid in situ testing of water quality.As a response to this issue, we propose to use acoustic transduction based on a surface acoustic wave (SAW) filter with the ultimate goal to realize biochemical detection in the field. SAW sensors are a good candidate to supply all the needed properties fo...

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Theoretical analysis of acoustoelectrical sensitivity in SAW gas sensors with single and bi-layer structures

Cited by 18 publications

References 13 publications

Surface Acoustic Wave Hydrogen Sensors Based on Nanostructured Pd/WO3 Bilayers

Surface Acoustic Wave Hydrogen Sensors Based on Nanostructured Pd/WO3 Bilayers

Development of Pd/TiO2 Porous Layers by Pulsed Laser Deposition for Surface Acoustic Wave H2 Gas Sensor

Mobile Acoustic Wave Platform Deployment in the Amazon River: Impact of the Water Sample on the Love Wave Sensor Response

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