scholarly journals Fast Response and High Sensitivity ZnO/glass Surface Acoustic Wave Humidity Sensors Using Graphene Oxide Sensing Layer

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Weipeng Xuan ◽  
Mei He ◽  
Nan Meng ◽  
Xingli He ◽  
Wenbo Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Glass Surface ◽  
High Sensitivity ◽  
Fast Response ◽  
Humidity Sensors

scholarly journals Hydrogen Gas Sensing Using Palladium-Graphene Nanocomposite Material Based on Surface Acoustic Wave

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Hai Ha ◽  
Nguyen Hoang Nam ◽  
Dang Duc Dung ◽  
Nguyen Huy Phuong ◽  
Phan Duy Thach ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Gas Sensing ◽  
Specific Interaction ◽  
High Sensitivity ◽  
Fast Response ◽  
Hydrogen Gas ◽  
Chemical Route ◽  
Response Recovery ◽  
Sensing Material

We report the fabrication and characterization of surface acoustic wave (SAW) hydrogen sensors using palladium-graphene (Pd-Gr) nanocomposite as sensing material. The Pd-Gr nanocomposite as sensing layer was deposited onto SAW delay line sensor-based interdigitated electrodes (IDTs)/aluminum nitride (AlN)/silicon (Si) structure. The Pd-Gr nanocomposite was synthesized by a chemical route and deposited onto SAW sensors by air-brush spraying. The SAW H2 sensor using Pd-Gr nanocomposite as a sensing layer shows a frequency shift of 25 kHz in 0.5% H2 concentration at room temperature with good repeatability and stability. Moreover, the sensor showed good linearity and fast response/recovery within ten seconds with various H2 concentrations from 0.25 to 1%. The specific interaction between graphene and SAW transfer inside AlN/Si structures yields a high sensitivity and fast response/recovery of SAW H2 sensor based on Pd-Gr/AlN/Si structure.

Surface Acoustic Wave Humidity Sensors Based on Graphene Oxide Thin Films Deposited with the Surface Acoustic Wave Atomizer

2012 ◽  
Vol 49 (1) ◽  
pp. 445-450 ◽  
Author(s):  
S. M. Balashov ◽  
O. V. Balachova ◽  
A. P. Filho ◽  
M. C. Q. Bazetto ◽  
M. G. de Almeida
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Oxide Thin Films ◽  
Humidity Sensors

scholarly journals Fabrication and Characterization of Flexible Capacitive Humidity Sensors Based on Graphene Oxide on Porous PTFE Substrates

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5118
Author(s):  
Zhenyu Wei ◽  
Jianqiu Huang ◽  
Wenhao Chen ◽  
Qingan Huang
Keyword(s):  
Graphene Oxide ◽  
Dynamic Properties ◽  
High Sensitivity ◽  
Fast Response ◽  
Humidity Sensors ◽  
Flexible Sensors ◽  
Response Recovery ◽  
Sensing Material ◽  
Fabrication And Characterization

Porous polytetrafluoroethylene (PTFE) is physically flexible, thermally and chemically stable, relatively inexpensive, and commercially available. It is attractive for various flexible sensors. This paper has studied flexible capacitive humidity sensors fabricated on porous PTFE substrates. Graphene oxide (GO) was used as a sensing material, both hydrophobic and hydrophilic porous PTFE as the substrates, and interdigitated electrodes on the PTFE substrates were screen-printed. SEM and Raman spectrum were utilized to characterize GO and PTFE. An ethanol soak process is developed to increase the yield of the humidity sensors based on hydrophobic porous PTFE substrates. Static and dynamic properties of these sensors are tested and analyzed. It demonstrates that the flexible capacitive humidity sensors fabricated on the ethanol-treated hydrophobic PTFE exhibit high sensitivity, small hysteresis, and fast response/recovery time.

Flexible Surface Acoustic Wave Based Temperature and Humidity Sensors

2014 ◽  
Vol 1659 ◽  
pp. 75-80 ◽  
Author(s):  
X.L. He ◽  
J. Zhou ◽  
W.B. Wang ◽  
W.P. Xuan ◽  
D.J. Li ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Lamb Waves ◽  
High Sensitivity ◽  
Zno Films ◽  
Humidity Sensors ◽  
Saw Devices ◽  
Flexible Surface ◽  
Temperature And Humidity ◽  
Temperature Coefficient Of Frequency

ABSTRACTFlexible surface acoustic wave (SAW) based temperature and humidity sensors were fabricated and characterized. ZnO piezoelectric films were deposited on polyimide substrates by DC magnetron sputtering. ZnO films possess (0002) crystal orientation with large grain sizes of 50∼70 nm. SAW devices showed two wave modes, namely the Rayleigh and Lamb modes, with the frequencies at fR ∼132MHz and fL∼427MHz respectively for a wavelength of 12 μm device. The two resonant frequencies have a temperature coefficient of frequency (TCF) of −423ppm/K and −258ppm/K for the Rayleigh and Lamb waves, respectively. The SAW sensors exhibited a good repeatability in responding to cyclic change of humidity. The responses of the sensors increase with the increase in humidity, and the sensitivity increases with the decrease in wavelength. A high sensitivity of 34.7 kHz/10%RH has been obtained from a SAW device without any surface treatment, demonstrated that the flexible SAW humidity sensors are very promising for application in flexible sensors and microsystems.

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