研究目的
To demonstrate the fabrication of arrays of vertical piezoelectric nanowires individually contacted at their base and their capability to act as self-powered sensors for mechanical strain mapping.
研究成果
The study successfully demonstrated the proof-of-concept of self-powered mechanical sensors based on vertical ZnO nanowires exploiting the piezoelectric effect. The technology developed is scalable and able to provide matrices of individual sensors. The electrical response was linear with flow rate and consistent with orientation, showing promising prospects for high-resolution mapping of force or deformation distribution.
研究不足
The fabrication process needs optimization to obtain only individual NWs in the device surface. An individual calibration of the contacted NWs is necessary to obtain the sensibility to a known lateral force or displacement. The NWs need to be encapsulated to improve the stability of the sensor and reduce its sensibility to gases.
1:Experimental Design and Method Selection:
The study used the hydrothermal method to grow vertical ZnO nanowires selectively between two pre-patterned electrodes. Nanowires deflection was produced by subjecting the array to an incident lateral gas flow of controlled rate, switched on and off repeatedly while measuring electrical response.
2:Sample Selection and Data Sources:
ZnO nanowires were grown on a silicon substrate with a gallium-doped ZnO seed-layer. The electrical response to strain was measured under different experimental conditions including flow rate, flow orientation, and nanowire position with respect to the tube outlet.
3:List of Experimental Equipment and Materials:
Karl Suss PM8 Probe station, Semiconductor analyzer (HP 4155A), Digital oscilloscope and function generator, Digital mass flow controller (MFC) – Horiba SEC-N100, ZnO nanowires, silicon substrate, gallium-doped ZnO seed-layer, gold metallic electrodes.
4:Experimental Procedures and Operational Workflow:
The samples were fixed on a chuck using vacuum. A controlled gas flow was directed to the sample through a plastic tube. The electrical response was measured in real time using the semiconductor analyzer while the gas flow was switched on and off.
5:Data Analysis Methods:
The electrical response of the device to nanowire bending was analyzed to test the device in its sensing mode. The current variation was recorded in real time and analyzed for different flow rates and orientations.
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