Summary: | 碩士 === 逢甲大學 === 自動控制工程學系 === 103 === The research develops nanofiber-based sensing structures based on the materials of polyvinyl pyrrolidone by using near-field electrospinning technique. The electrospinning process parameters are analyzed to characterize properties of the spun fibers. The near-field electrospinning technology using direct write, continuous and controllable method is used to deposit solid nanofibers. The nanofibers are deposited on the collector by stretching and whipping rejection process. Polyvinyl pyrrolidone is used to electrospun nanofibers. The research develops polyvinyl pyrrolidone nanofibers field-effect transistor-based sensor is fabricated by electrospinning, photolithography, and lift-off processes to measure and analyze the electrical property. The advantages of the field-effect transistor-based sensor combined polyvinyl pyrrolidone nanofibers and metal electrodes in the chip have small volume, high precision and high sensitivity. Based on traditional field effect transistor principle and characteristic, the charges flow passes through the drain-source current characteristics which is discussed by apply different gate voltages. Experiment and investigate are excuted for effects of different channel length and numbers of nanofiber, operating voltage, current and resistance correlation. And I-V characteristics of MOS transistors are obtained. The output voltage is limited in the range of -5 V to 5 V, and the linear operation region of this element is-2 V~2 V. A single nanofiber and ten nanofibers channel structure devices has resistance 5.8 MΩ and 5.6 MΩ in the channel lengths between 100 and 500 μm. The measured current were 36 nA and 39.3 nA. A single nanofiber and ten nanofibers channel structure devices has resistance 13.01 MΩ and 13.03 MΩ in the relative humidity between 30 and 70 % on the channel lengths 100 μm. The threshold voltage of devices is 35 V. When the drain-source voltage is operated less than 20 V, the linear dependence of current-voltage relationship is obtained. When the drain-source voltage is operated greater than 45 V, the current becomes saturation.
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