Dielectrophoretic manipulation of nano-materials and its application to micro/nano-sensors

Dielectrophoresis is a potential technique which can be employed to align and manipulate nano-structured materials to the preset locations in fluid for electronic device applications in micro/nano-sensors and circuits. In this paper, with several home-made electrode pairs, we succeeded in manipulating the micro/nano-particles along the electric field and depositing them across the gaps between two electrodes. It is proven as a helpful experiment to assemble the nano-structures with precise arrangement. A relative humidity sensor, using the dielectrophoretically assembled self-grown nano-materials as a sensing element, was fabricated and the sensing properties were then tested. The sensitivity increased with the decline of the testing frequency. And a high humidity sensitivity of 146.90 kΩ/RH% was obtained with a testing frequency of 100 Hz. The relativity of the impedances measured at the same frequency was above −0.90. The relative standard deviations were small especially under a lower relative humidity level. The comparison between aligned and not-aligned nano-materials in the sensing structures was presented to verify the work of the dielectrophoresis. The detection result confirmed the feasibility of applying nano-materials located between the electrodes by dielectrophoresis as sensing elements to micro/nano-sensors.