| Summary: | 碩士 === 長庚大學 === 電子工程學系 === 101 === We propose a convenient and flexible bottom-up approach for specific arranging single nanowire onto a pair of defined electrode by using the combination of optically-induced dielectrophoresis and dielectrophoresis. After the nanowire was attracted on the electrodes, it was further fixed on the electrode by depositing platinum on two ends of nanowire using focus ion beam system to reduce the contact resistance.
In this work, we use amorphous silicon as a photoconductive layer for the optically-induced manipulation. The nanowire was manipulated to be near the electrode by optically-induced dielectrophoresis and was then attracted onto the electrodes by applying an A.C. signal on electrode to generate the dielectrophoresis force. After the nanowire was connected between the gap of two electrodes, it was fixed on the electrode by depositing platinum on two ends of nanowire using FIB, and then the sensing area of nanowire was defined by photolithography. After the nanowire was assembled, the I-V characteristic of nanowire sensor was measured. Experimental data show that the contact resistance was reduced by platinum deposition. The conductance increased from 3.26 pS (without platinum deposition) to 59.88 pS (with platinum deposition). In addition, the coefficient of variation of the conductance was improved from 82% to 12%. In the approach we provided, it only took around 24 s for each nanowire connection. The successful percentage of nanowire connection between the gap of two electrodes is nearly 100% which is higher than using conventional dielectrophoresis method (98.5%).
The combination of ODEP and DEP force provides an efficient approach for assembling a specific nanowire to a specific pair of metal electrodes, which was not easily achieve by other techniques.
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