| Summary: | 碩士 === 國立交通大學 === 光電工程系所 === 97 === IN this thesis, we modify the functional groups to obtain diversity of organic thin-film transistors (OTFTs) gas sensing ability. By using self-assembled monolayer (SAMs) treatment, the silicon oxide surface (SiO2) was modified by 3-amino-propyltriethoxysilane (APTES) and n-octadecyltrimethoxysilane (ODMS). Both ODMS and APTES (with amine groups) were hydrophobic, which served a low surface-energy surface for pentacene film growth. Therefore, the interface properties between pentacene film and SiO2 will be significantly changed. The OTFTs with interface modifications was then used as gas sensors. During gas sensing, in our previous reports, the gated-four-probes method was also used to analyze the changes of contact resistance and pentacene-film resistance. It was shown that with interface modifications, pentacene film resistance variation will become a key factor in gas sensing. However, the contact resistance was dominated factor that influenced gas sensing. The contrary results can be explained by the different SAMs will result in different pentacene structure or thin-film carrier density, which influenced the OTFTs interaction to gases. Additionally, multiple parameters such as mobility, threshold voltage, and sub threshold swing were also used to analyze gas sensing interactions. Base on this result, we prove how to increase sensing ability of a specific material with functional groups modification on silicon oxide interface. In Cwei-Chou and Yuanren Lo’s instruction, we cooperate together and finish this research.
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