官能基修飾有機薄膜電晶體氣體感測之研究

Abstract

在此論文中,我們藉由修改官能基來得到有機薄膜電晶體(OTFTs) 氣體變化感覺能力。利用自組裝單層膜(SAM)的方式,在氧化曾上分別修飾了三氨□丙基三乙氧基硅烷以及十八烷基三甲氧基硅烷.由於三氨□丙基三乙氧基硅烷以及十八烷基三甲氧基硅烷都是疏水層,因此會造成低表面能以利於五環素成長.因此氧化層與pentacene間的表面性質已經改變.而藉著改變表面態後的OTFTs來當作氣體感測器.對於氣體感應器, 在我們的之前的研究,四點探針的方法用來研究寄生電阻以及薄膜電阻的改變.同時也顯示出,經過表面處理修飾後,pentacene薄膜電阻變化似乎已經變成主要因素,對於氣體感應而言.但是,寄生電阻是影響氣體感應的控制因素。相反結果,也可能由不同的SAMs解釋導致pentacene 結構或薄膜載子密度, 進而影響OTFTs 與氣體間的反應。另外, 多個參數,譬如載子遷移率、臨界電壓, 和次臨界擺幅並且使用分析氣體感應互作用。基於在這個結果下, 我們證明怎麼增加對專一氣體的感應能力,在藉由官能基修飾氧化層的方法下。在羅淵仁學長以及周政偉學長的指導下,一起合作進行此研究。

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.