本文結合原子力顯微術奈米加工技術(Atomic Force Microscopy Nanomachining)及光學微影技術(Photolithography),製作以單根金奈米線(Single Gold Nanowire)為基礎的電阻式化學感測器(Resistive-Type Chemical Sensor)。感測原理是由於自組裝分子(Self-assembled Monolayer, SAM)會與金奈米線形成化學鍵結,使其電阻值會因導電電子在傳輸過程中與表面的散射效應增加而上升,並以此作為感測依據。本文使用了兩種不同的溶液,十八烷硫醇及十二烷硫醇分子,並分別與金奈米線做化學吸附反應,發現當奈米線表面完全吸附上硫醇分子時,其電阻值增加率皆達到約9%。另外,也推導出電阻改變率與硫醇濃度的理論關係式,與實驗結果相當符合。
We report a resistive-type chemical sensor based on a single gold nanowire fabricated by a combination of atomic force microscopy nanomachining and conventional photolithography. The chemical sensing capability is demonstrated by the selective binding of a self-assembled monolayer onto a single Au nanowire and the subsequent resistance increase due to increased surface scattering. It is found that the resistance increases by around 9% after the complete coverage of either octadecanethiol or dodecanethiol molecules onto the Au nanowire. A theoretical explanation for the relationship between the resistance increase and the thiol concentration is also given and found to be in excellent agreement with experimental results.