低溫水熱法合成二氧化錫奈米線結構應用於高效能酸鹼與葡萄糖生醫感測器之研究

Abstract

近年來，二氧化錫材料之奈米結構元件已有相當的研究及發展。用來製備一維之二氧化錫奈米線的方法多數皆採用高溫製程，因此，複雜的製程與昂貴的儀器設備便成為二氧化錫材料奈米結構化之不可或缺的要素。為了簡單化製程以及降低成本，本論文成功地利用95∘C低溫水熱法合成二氧化錫奈米線與薄膜之金紅石結構。 再者，於前人的研究中發現，二氧化錫於酸鹼值感測器應用方面具備良好之特性表現，因此，本實驗將水熱法合成之二氧化錫奈米線與薄膜結構應用於酸鹼值感測與葡萄糖感測。不同於以往之平面式感測膜，本論文中將二氧化錫奈米線結構作為延伸式閘極場效電晶體之感測膜層，此奈米結構化之二氧化錫將大幅改善其感測特性。在特性表現方面，二氧化錫奈米線之結晶性較薄膜結構為佳；由電性分析中可得知，二氧化錫奈米線感測器於量測範圍自pH 1~pH 13間進行酸鹼值感測時擁有較高的電壓感測靈敏度 (55.18 mV/pH)、較高的電流感測靈敏度 (0.86 μA1/2/pH)、以及較好的線性度 (0.9964)。而在相同的量測環境下，二氧化錫薄膜感測器之電壓感測靈敏度為48.04 mV/pH、電流感測靈敏度為0.79 μA1/2/pH、線性度則為0.9963。此外，遲滯效應與電壓時漂效應之量測結果顯示二氧化錫奈米線感測器具有卓越的可靠度與耐久性。奈米結構化的過程促使感測膜之比表面積大幅增加，而比表面積增加後使得於感測膜層表面的不完整鍵結數量亦同時增多，反映於電特性表現上使二氧化錫奈米線酸鹼感測器之感測靈敏度相較於二氧化錫薄膜酸鹼感測器增加了15%。而在葡萄糖感測之研究中，二氧化錫奈米線感測器在量測範圍自60 mg/dl to 360 mg/dl間有高達0.661 mV(mg/dl)−1 (=11.89 mV/mM)之感測度。除此之外，無論是二氧化錫奈米線感測器亦或是二氧化錫薄膜感測器，於高濃度 (360 mg/dl)葡萄糖溶液中之響應時間皆較其於低濃度 (60 mg/dl)葡萄糖溶液中為迅速。

SnO2 nanostructure-based devices have been applied and paid considerable attention currently. Many high-temperature approaches have been presented for the synthesis of one-dimensional SnO2 nanotructures. However, those approaches not only encountered difficult fabrication but also required expensive facilities. In this thesis, the SnO2 nanorods and thin film with rutile structure have been successfully synthesized by using a simple and low cost hydrothermal method at a temperature as low as 95℃. Additionally, SnO2 as the sensing membrane has attracted considerable interests as pH sensor. Thus, the hydrothermally synthesized SnO2 nanorods and thin film were applied in the pH and glucose sensors. In the thesis, an extended-gate field-effect transistor (EGFET) with such SnO2 nanorods therefore proposed as a high performance pH/glucose sensor. The crystallinity of SnO2 nanorods was relatively better than the SnO2 thin film. Accordingly, The sensing characteristics of SnO2 nanorods exhibited the higher voltage sensitivity of 55.18 mV/pH, higher current sensitivity of 0.86 μA1/2/pH, and larger linearity of 0.9964, correspondingly, in the sensing range of pH 1 to pH 13 for the pH sensor with respect to voltage sensitivity of 48.04 mV/pH, current sensitivity of 0.79 μA1/2/pH, and linearity of 0.9963 for the SnO2 thin film one. Both the hysteresis drift curve and voltage-time drift measurement of the SnO2 nanorod sensor indicated excellent reliability and durability. It suggested the 15% sensitivity improvement was majorly attributed to high surface-to-volume ratio of nanorod structure, reflecting amount of sensing sites. Furthermore, the sensing characteristics of SnO2 nanorods also exhibited the marvelous output sensitivity of 0.661 mV(mg/dl)−1 (=11.89 mV/mM) from 60 mg/dl to 360 mg/dl for the glucose measurement. Besides, the SnO2 glucose sensors show the faster response time for the glucose concentration of 360 mg/dl than the 60 mg/dl one.