本論文主要研究高立體規則性之有機高分子半導體聚(3-己烷基塞吩) （poly(3-hexylthiophene)，RR-P3HT）為主動層之上閘極式薄膜電性晶體的元件特性。首先，利用旋轉塗佈法製作RR-P3HT薄膜當主動層，再於其上堆疊高分子絕緣材料當作介電層，最後鍍上金屬電極當閘極，製作上閘極式電晶體元件。本研究主要進行後續沉積數種高分子絕緣層對RR-P3HT主動層薄膜微結構與半導體特性的影響，並探討各種高分子絕緣層對電晶體元件電特性的影響。
首先，利用進行高分子絕緣層介電特性研究，由電容－電壓量測得知交聯結合的poly(4-vinylphenol)(C-PVP)高分子適合當主介電層材料，但並不適合直接沉積在RR-P3HT薄膜上，因此本論文聚焦於導入一個高分子緩衝層對RR-P3HT上閘極式電晶體元件的影響，本文使用聚偏氟乙烯 (PVDF)、聚乙烯吡咯烷酮 (PVnP) 、聚甲基丙烯酸甲酯 (PMMA) 、聚乙烯醇(PVA)當做緩衝層，結果指出PVDF當做緩衝層(buffer layer)所製作之上閘極電晶體元件，有最佳載子遷移率可達0.1 cm2/Vs 以上，因此建議覆蓋緩衝層將可有效保護RR-P3HT主動層，製作出高性能元件。
於第四章，吾人利用紫外－可見光吸收光譜與拉曼光譜進行有無覆蓋高分子絕緣層之RR-P3HT薄膜微結構解析，結果指出使用PVDF當緩衝層可以幫助減緩C-PVP對RR-P3HT的影響，並可幫助到RR-P3HT分子鏈重排，獲致更佳的微結構，有助於載子的傳遞，提供一個上閘極式元件電性改善的合理解釋，而其他的高分子緩衝層則無此效果。

In this thesis, we studied the thin-film microstructures and electrical characteristic of regioregular poly(3-hexylthiophene) (RR-P3HT)-based organic thin-films transistors (OTFTs) with top-gate structure. First, the RR-P3HT active layer was prepared by solution deposition through a spin-coating technique. Then, the polymeric insulators were coated onto RR-P3HT film and serve as the gate dielectrics. After preparation of the polymeric dielectrics, finally, the metal electrode was deposited upon the dielectric surface and served as a top gate electrode of the OTFT devices. We present a systematic study involving the change of the microstructural and semiconductor properties of the RR-P3HT active layer in the OTFT devices during subsequent fabrication of solution processed polymeric gate dielectrics.
First, the dielectric characteristics of polymer insulators were studied by capacitance-voltage measurements. Here, we chose a crosslinked-poly(vinylphenol) (C-PVP) as the main gate dielectric due to its good capacitance properties. We demonstrated that a high mobility of above 0.1 cm2/Vs in RR-P3HT-based top-gate OTFTs with a C-PVP gate dielectric can be achieved by introducing particular polymeric buffer layers, i.e., poly(vinylidene difluoride) (PVDF). Additionally, we also made other polymer insulators to use in a buffer layer upon the RR-P3HT films, such as poly(vinyl pyrrolidone) (PVnP), poly(methyl methacrylate) (PMMA), and poly(vinly alcohol) (PVA); unfortunately, we could not observe significant structural and charge mobility improvements in the RR-P3HT-based tog-gate OTFT devices.
In chapter 4, we studied the structural properties of RR-P3HT films before and after covering various multilayer stacks of polymer insulators by UV-Vis absorption and Raman spectroscopy. The results revealed that covering the PVDF/C-PVP bilayer dielectrics resulted in a more ordered structure of RR-P3HT films. To the contrary, we could not observe significant structural improvements of RR-P3HT films when other polymer insulators, e.g., PVnP, PMMA, and PVA, were used as the buffer layer. The observations provided a reasonable explanation for better device performance of RR-P3HT top-gate OTFTs when using PVDF as a buffer layer. Consequently, we suggested that the used buffer layer in top-gate RR-P3HT OTFTs played an important role, not only in RR-P3HT thin film structures but also the corresponding OTFT characterizations.

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