以不同粒徑金奈米粒子修飾之氧化鋅奈米線在濕度感測的應用

Abstract

在本論文中，我們使用金奈米粒子的修飾以介電泳動技術製作之空橋式氧化鋅（ZnO）奈米線的感測器元件，除了分析退火時間對金奈米粒子形成的影響，也討論該元件對於濕度變化的電性響應。我們首先在矽基板上沉積二氧化矽作為絕緣層，再利用標準黃光微影技術定義出電極的位置，並利用電子束蒸鍍機鍍上鈦金屬搭配金屬掀離製程(Lift off)製作電極，接著使用介電泳動技術定位奈米線到特定電極上以製作出空橋結構，最後再使用蒸鍍機鍍上金粒子並進行退火製備出氧化鋅奈米線感測器。 透過以上製程，我們計算了退火時間對金奈米粒子大小的影響，也對經過不同退火時間之單純的氧化鋅和金奈米粒子修飾之氧化鋅奈米線元件進行不同濕度下的電性量測，並發現鍍有金奈米粒子的樣品在相同濕度下會具有較大的電流，另外也針對這兩種不同的樣品，改變環境相對濕度，同樣進行電流響應和反應時間的量測。量測結果也展現了經過金奈米粒子修飾的樣品在響應上優勢。

In this research work, we decorated bridged zinc oxide (ZnO) nanowires with Au nanoparticles. These nanowires were fabricated by dielectrophoretic deposition techniques. Subsequently, we analyzed Au nanoparticles formed under different annealing times and discussed the electrical response of these devices to humidity changes. First of all, we deposited SiO2 as an insulating layer on a silicon substrate. Then, standard photolithography was used to define the electrode positions, and an electron-gun evaporator was applied to deposit Ti metal, followed by a lift-off process to fabricate the electrodes. By utilizing dielectrophoretic methods, we precisely positioned nanowires onto specified electrodes to form a bridged structure. Finally, gold nanoparticles were deposited using an electron-gun evaporator and annealed to fabricate the Au-decorated ZnO nanowire sensor. Through this process, we made statistics of the impact of annealing time on the size of gold nanoparticles. We also performed electrical measurements under different humidity conditions on both pure ZnO nanowire devices and those modified with gold nanoparticles. It was found that samples with gold nanoparticles exhibited higher current at the same humidity levels. Furthermore, for these two type samples, we measured the current response and response time by varying the relative humidity of the environment. The measurement results also demonstrated the advantages of the gold nanoparticle-modified samples in terms of response.