可撓式有機電晶體製備與特性研究

Studies on the Fabrication and Characteristics of Flexible Organic Thin-Film Transistors

陳映豪(Ying-Hao Chen)

指導教授 ： 郭欽湊

大同大學/工程學院/化學工程學系所/碩士(2009年)

摘要

本論文研究主要是探討撓曲性薄膜電晶體之特性以五環素為半導體層，以聚對苯二甲酸乙二酯(poly(ethylene terephthalate); PET)為塑膠基板分別利用不同高分子[例如: 聚醯胺樹酯Poly(dimer acid-co-alkyl polyamine) (PA)、聚甲基丙烯酸甲酯 poly(methyl methacrylate) (PMMA)、聚苯乙烯 polystyrene (PS)] 作為介電層材料，探討高分子介電層表面形態(粗糙度)與親水性/疏水性對電晶體特性的影響；藉self-assembled monolayer (SAM) 處理金閘極電極期望改善表面粗糙度；使其進一步改變五環素之結晶特性，進而改善元件之特性。
利用雙層閘極介電層製作上接觸式可撓曲式有機薄膜電晶體之電特性皆比單層介電層來的好，證實雙層介電層能增加介電層之絕緣性，因此雙層介電層能有效降低off current，致使開關電流比可達到105~106，平坦的PMMA/PA(0.57 nm )和PS/PA(0.49 nm )表面沉積上五環素(pentacene)，可獲得較大的結晶顆粒(＞1 μm)，亦可減少晶粒邊界的能障損失而增加電洞的傳遞之速度，有助於提升元件之特性(元件結構Au/pentacene/PMMA/PA/Au之開關電流比2.79×105、起始電壓-15.6 V、場效位移率1.72 cm2/Vs、元件結構Au/pentacene/PS/PA/Au之開關電流比1.18×106、起始電壓-37.1 V、場效位移率1.28 cm2/Vs )。

探討有機電晶體之穩定性和實用性，元件進行磁滯現象測試和彎曲實驗。由特性曲線圖發現在off state 有顯著的磁滯現象；進行彎曲測試實驗，元件特性隨彎曲次數增加而下降。

關鍵字

五環素 ； 可撓式薄膜電晶體 ； 位移率

並列摘要

The main purpose of this thesis studies on the characteristics of flexible thin-film transistor (TFT) fabricated with pentacene as a semiconductor layer, poly(ethylene terephthalate) (PET) as a plastic substrate, and different kinds of polymeric [ such as poly(dimer acid-co-alkyl polyamine) (PA), poly(methyl methacrylate) (PMMA), and polystyrene (PS) ] as a gate dielectric. Studies on the performance of device can be affected by morphologies (roughness) and hydrophile/hydrophobe of polymeric dielectric is to be carried out. By self-assembled monolayer (SAM) treatments, which were expected to improve the surface roughness of Au gate electrode, the improvement on the roughness of the Au gate electrode changed the crystallization characteristics of the pentacene and improved the characteristics of device.
The performance of flexible top-contact thin-film transistors fabricated with polymer dielectric dual layer was better than that of device fabricated with single layer. The confirmation of using the dual dielectric layer fabrication can increase the insulator properties of dielectric. Because of dual layer can decrease significantly of the off current and such that the on/off current ratio increased to about 105~106. The pentacene deposited on the smooth PMMA/PA and PS/PA dielectric layer can improve the packing of pentacene molecules and the compatibility and adhesion of interface between the active layer and the insulator, an effect very suitable for charge transporting, then helpful promoted device performance (The characteristics of Au/pentacene/PMMA/PA/Au OTFT are on/off current ratio of 2.79 × 105, threshold voltage of -15.6 V, and mobility of 1.72 cm2/Vs and one of Au/pentacene/PS/PA/Au OTFT are on/off current ratio of 1.18 × 106, threshold voltage of -37.1 V, and mobility of 1.28 cm2/Vs).
Studying organic thin-film transistor with stability and practice to test the hysteresis phenomenon and blending experiment are to be carried out. The phenomenon of hysteresis occurred at off state from the diagrams of characteristic curves. It is found that the characteristics of the devices decrease with the increasing the bending times.

並列關鍵字

pentacene ； flexible thin-film transistor ； mobility

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