本文研究以高分子半導體regioregular poly(3-hexylthiophene) (RR-P3HT) 為主動層之有機薄膜電晶體的載子傳輸性質。第一部份，使用RR-P3HT混摻一絕緣性高分子poly(methyl methacrylate) (PMMA)當主動層，研究固態結構與載子傳輸特性的關係。第二部份，研究長時間操作下RR-P3HT元件載子傳輸的穩定性，探討偏壓應力對RR-P3HT固態薄膜結構與對應元件電性的影響。
　　第一部份，首先利用X-ray繞射、吸收光譜與拉曼光譜研究不同混摻比例RR-P3HT/PMMA薄膜的固態結構，結果指出掺合PMMA會降低RR-P3HT鏈間的交互作用與RR-P3HT的有效共軛鏈長，阻礙RR-P3HT形成片狀結晶結構，並使RR-P3HT在掺合薄膜中的排列較無次序性。電性方面，純RR-P3HT的元件，受雜質與環境（如水、氧）影響甚大，無法形成理想的場效通道，藉由掺合PMMA可改善此現象，但RR-P3HT於摻合薄膜中，表現出較差的載子傳輸特性，歸因於稀釋效應與較差的結晶結構。
　　第二部份，在高真空量測環境下，長時間的偏壓應力對RR-P3HT有機薄膜電晶體的載子遷移率沒有產生任何退化，但導通電流會降低，臨界電壓往負電壓的方向漂移，導通電流與臨界電壓的變化在偏壓應力停止後，經過長時間也無法完全恢復到初始值。固態結構方面，利用偏極化吸收光譜與偏極化拉曼光譜研究偏壓應力對RR-P3HT固態薄膜結構的影響，結果指出長時間的偏壓應力會增加RR-P3HT鏈間的交互作用，並產生異向性，平行電場方向的增加幅度大於垂直電場方向。

　　In this study, electronic transport properties of regioregular poly(hexylthiophene) (RR-P3HT) based organic thin-film transistors (OTFTs) were investigated. In part 1, the correlation between thin-film structure and carrier transport properties were investigated using RR-P3HT blending poly (methyl methacrylate) (PMMA) as an active layer in OTFTs. In the second part, bias-stress induced electronic characteristics variation of RR-P3HT-based OTFTs and structural changes of RR-P3HT active layer were studied.
　　Part 1: The RR-P3HT/PMMA blend films with different weight fractions were fabricated and their characteristics were analyzed using X-ray diffraction (XRD), absorption spectroscopy, and Raman spectroscopy. Structural analysis revealed that blending of PMMA reduced interchain interaction and efficient conjugation length of RR-P3HT, interrupted RR-P3HT to form lamellar microstructures, and increased the RR-P3HT chain disorder. Analysis of electric characteristics suggests that poor performance of the neat RR-P3HT OTFTs in air occurs due to the humidity and oxygen in air ambient, consequently limiting the formation of ideal field-effect channel. The phenomenon was improved by blending the PMMA into the RR-P3HT and thus inducing a sharper field-effect channel. However, we observed inferior field-effect mobilities in RR-P3HT/PMMA blends due to the dilute effect and inferior structure of RR-P3HT.
　　Part 2: The long-term electronic stability of RR-P3HT-based OTFTs were studied and the corresponding thin-film structure of RR-P3HT were also analyzed using XRD, absorption spectroscopy, and polarized Raman spectroscopy. After long-term bias stress, we have not found significant degradation in the field-effect mobility of RR-P3HT-based OTFTs in vacuum environment. However, the bias stress induced a decreasing output on-current, while threshold voltage shifted towards negative. The process was found to be partially irreversible. Structural analysis showed that the interchain interaction of RR-P3HT could be enhanced after long-term bias stress, thus resulting in occurrence of slight structural anisotropy, especially in the direction parallel to source-to-drain field.

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