Implementation of ZnO Nanorods as Sensing Elements for a Surface Acoustic Wave Sensor

The limited sensitivity of thinfilm based sensors has motivated the search for sensing structures and materials with greater sensing performance. Although thinfilm based SAW devices have been used as force, pressure, chemical and gas sensors so far. It is limited by the exposed sensing surface of the thinfilm. A feasibility study has been done by implementing the ZnO nanorods (NRs) to enhance the device sensitivity by greatly increase the exposed sensing surface. The implementation of these ZnO NRs as sensing elements is expected to enhance the sensing power due to the large surface to volume ratio. The sensing mechanism in this design is by detecting the minute change of seismic mass for ZnO NRs using surface acoustic wave before and after the attachment of reacting chemical liquid and gas substance.

Download Full-text

A passive wireless hydrogen surface acoustic wave sensor based on Pt-coated ZnO nanorods

Nanotechnology ◽

10.1088/0957-4484/21/9/095503 ◽

2010 ◽

Vol 21 (9) ◽

pp. 095503 ◽

Cited By ~ 35

Author(s):

Ya-Shan Huang ◽

Yung-Yu Chen ◽

Tsung-Tsong Wu

Keyword(s):

Acoustic Wave ◽

Surface Acoustic Wave ◽

Zno Nanorods ◽

Acoustic Wave Sensor

Download Full-text

Characterization of Group III-Nitride Based Surface Acoustic Wave Devices for High Temperature Applications

MRS Proceedings ◽

10.1557/opl.2011.396 ◽

2011 ◽

Vol 1299 ◽

Cited By ~ 3

Author(s):

J. Justice ◽

L.E. Rodak ◽

V. Narang ◽

K. Lee ◽

L.A. Hornak ◽

...

Keyword(s):

Acoustic Wave ◽

Surface Acoustic Wave ◽

Harmonic Excitation ◽

Scattering Parameter ◽

Group Iii ◽

Saw Devices ◽

Before And After ◽

Metal Organic ◽

Acoustic Wave Devices ◽

Group Iii Nitride

ABSTRACTIn this study, aluminum nitride (AlN) and gallium nitride (GaN) thin films have been grown via metal organic vapor phase epitaxy (MOVPE) on silicon and sapphire substrates. Samples were annealed at temperatures ranging from 450 to 1000 °C in atmosphere. AlN and GaN thin film quality has been characterized before and after annealing using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM). Surface acoustic wave (SAW) devices with titanium/platinum interdigital transducers (IDTs) designed to operate at the characteristic frequency and fifth harmonic have been realized using traditional optical photolithographic processes. SAW devices on GaN were thermally cycled from 450 to 850 °C. The S21 scattering parameter of SAW devices was measured before and after thermal cycling by a vector network analyzer (VNA). An approach for the suppression of electromagnetic feedthrough (EF) to improve device performance is discussed. Feasibility of 5th harmonic excitation for GHz operation without sub-micron fabrication is also investigated. SAW devices have also been fabricated on the more traditional SAW substrate, lithium niobate (LiNbO3), and device response was compared with those on AlN and GaN at room temperature.

Download Full-text

ZnO Surface Acoustic Wave Sensor for the Enhanced Detection of DMMP

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.185.69 ◽

2012 ◽

Vol 185 ◽

pp. 69-72 ◽

Cited By ~ 5

Author(s):

V. Bhasker Raj ◽

Monika Tomar ◽

A.T. Nimal ◽

Yashoda Parmar ◽

M.U. Sharma ◽

...

Keyword(s):

Acoustic Wave ◽

Surface Acoustic Wave ◽

Chemical Warfare Agent ◽

Sensing Mechanism ◽

Enhanced Sensitivity ◽

Saw Devices ◽

Increase With Increase ◽

Water Vapors ◽

Acoustic Wave Sensor ◽

Volatile Organic

This article reports the development of ZnO coated one port Surface Acoustic Wave (SAW) resonators for the detection of DMMP (dimethyl methyl phosphonate), a simulant of chemical warfare agent Sarin at room temperature. For enhanced sensitivity high frequency SAW devices (433Mhz) were used. Frequency shift with DMMP exposure was found to increase with increase in thickness of ZnO film from 20 to 80 nm with maximum shift of 52 kHz. The cross sensitivity of the sensor with commonly available volatile organic compounds (VOCs), gases and water vapors has been performed and was found that the sensitivity towards other interferants is very less as compared to that of DMMP vapors. The sensing mechanism has been explained in detail. It has been shown that there was no significant change in the resistance of the film with exposure to DMMP vapors and hence the contribution of the acoustoelectric interaction is negligible. Further mass loading was not dominant. The negative differential frequency shifts proved that change in elasticity of the film with exposure to DMMP vapors is the dominant sensing mechanism.

Download Full-text

Investigation into surface acoustic wave sensor for DCM gas detection using COMSOL multiphysics

Ferroelectrics ◽

10.1080/00150193.2020.1868875 ◽

2021 ◽

Vol 572 (1) ◽

pp. 94-105

Author(s):

Mohamed Moustafa ◽

Ghaylen Laouini ◽

Mostafa ElNaggar ◽

Tariq AlZoubi

Keyword(s):

Acoustic Wave ◽

Surface Acoustic Wave ◽

Gas Detection ◽

Comsol Multiphysics ◽

Acoustic Wave Sensor

Download Full-text

On the Performance Evaluation of Commercial SAW Resonators by Means of a Direct and Reliable Equivalent-Circuit Extraction

Micromachines ◽

10.3390/mi12030303 ◽

2021 ◽

Vol 12 (3) ◽

pp. 303

Author(s):

Giovanni Gugliandolo ◽

Zlatica Marinković ◽

Giuseppe Campobello ◽

Giovanni Crupi ◽

Nicola Donato

Keyword(s):

Performance Evaluation ◽

Acoustic Wave ◽

Equivalent Circuit ◽

Surface Acoustic Wave ◽

Equivalent Circuit Model ◽

Practical Applications ◽

Saw Devices ◽

S Parameter ◽

Commercial Device ◽

Saw Resonators

Nowadays, surface acoustic wave (SAW) resonators are attracting growing attention, owing to their widespread applications in various engineering fields, such as electronic, telecommunication, automotive, chemical, and biomedical engineering. A thorough assessment of SAW performance is a key task for bridging the gap between commercial SAW devices and practical applications. To contribute to the accomplishment of this crucial task, the present paper reports the findings of a new comparative study that is based on the performance evaluation of different commercial SAW resonators by using scattering (S-) parameter measurements coupled with a Lorentzian fitting and an accurate modelling technique for the straightforward extraction of a lumped-element equivalent-circuit representation. The developed investigation thus provides ease and reliability when choosing the appropriate commercial device, depending on the requirements and constraints of the given sensing application. This paper deals with the performance evaluation of commercial surface acoustic wave (SAW) resonators by means of scattering (S-) parameter measurements and an equivalent-circuit model extracted using a reliable modeling procedure. The studied devices are four TO-39 packaged two-port resonators with different nominal operating frequencies: 418.05, 423.22, 433.92, and 915 MHz. The S-parameter characterization was performed locally around the resonant frequencies of the tested SAW resonators by using an 8753ES Agilent vector network analyzer (VNA) and a home-made calibration kit. The reported measurement-based study has allowed for the development of a comprehensive and detailed comparative analysis of the performance of the investigated SAW devices. The characterization and modelling procedures are fully automated with a user-friendly graphical user interface (GUI) developed in the Python environment, thereby making the experimental analysis faster and more efficient.

Download Full-text