隨著資訊技術以及大數據分析的快速發展，僅依靠Von Neumann架構的電腦已逐漸無法滿足技術發展的需求，因此受大腦神經運作形態啟發而興起的人工突觸元件獲得越來越多的關注，其具有仿大腦的學習、記憶功能及低功耗的優點。隨著時間的推移，從僅以無機材料或有機材料製成的電突觸元件，到現今結合鈣鈦礦、二維材料、有機材料…等等製成的光感突觸元件，以及從基本的單一輸入對單一輸出的突觸元件，到現今多輸入對單輸出，甚至多輸入對多輸出的突觸元件，可看出突觸元件已發展出更多且更複雜的功能性。本論文將以不同製程條件製作聚(3-己基噻吩)(Poly(3-hexylthiophene), P3HT)薄膜，並貼附固態電解質介電層製作電晶體元件，研究P3HT製程條件對於電晶體元件模擬人工突觸系統中的突觸特性的影響，並深入探討其中的物理機制。
本論文分為三個部分，首先以不同的製程條件製作P3HT薄膜，分別利用旋轉塗佈熱退火成膜(Spin-coated thermal annealing films, 簡稱ST薄膜)、旋轉塗佈自由成膜 (Spin-coated free standing films, 簡稱SF薄膜)以及滴落塗佈自由成膜(Drop-casted free standing films, 簡稱DF薄膜)三種不同製程製作，並透過原子力顯微鏡(Atomic Force Microscopy, AFM )、白光干涉儀、X-ray 繞射分析儀(X-Ray Diffractometer, XRD)及吸收光譜分析各種P3HT薄膜的結構特性，並發現以滴落塗佈自由成膜的製程方法有利於分子向上堆疊與形成較佳週期結構。
第二部分使用上述P3HT薄膜作為主動層製成固態電解質電晶體，並量測元件的電晶體電特性及仿突觸相關特性曲線，發現ST-P3HT、SF-P3HT、與DF-P3HT 元件均可藉由接收單一至複數刺激後，產生類似突觸特性的反應，其中DF-P3HT元件的電流傳遞速率較佳且電荷累積效應較好，歸因於主動層內P3HT結晶度較好，也由此使元件具有突觸中的長期增強效應(Long-term potentiation, 簡稱LTP)。
第三部分，製作具平面閘極結構(In plane gate, 簡稱IPG)的元件，使元件具有多輸入對單輸出的設計，並以模擬神經調節相關特性的量測為重點，經由給予不同閘極刺激，發現ST-P3HT元件無法模擬神經調節效果，而SF-P3HT與DF- P3HT元件則皆能模擬神經調節中的異突觸易化(Heterosynaptic facilitation)與突觸前抑制(Presynaptic inhibtion)。當元件應用於邏輯運算時，發現SF-P3HT與DF-P3HT元件可藉由改變IPG正負電壓的刺激，切換YES與OR的邏輯操作；SF-P3HT元件則可切換OR與XOR的邏輯操作。
實驗結果指出ST-P3HT元件的突觸功能性較SF-P3HT與DF-P3HT元件少，DF-P3HT元件的基本電性與突觸特性均較SF-P3HT元件佳。然而，若使用多閘極結構，SF-P3HT元件反而在模擬邏輯功能性上較ST-P3HT與DF-P3HT元件多。

In this thesis, three kinds of poly(3-hexylthiophene-2,5-diyl) (P3HT)-based organic thin-film transistors (OTFTs) with a solid-state electrolyte dielectric layer were fabricated and used as artificial synaptic devices. The corresponding electrical characteristics and synaptic behavior were studied. P3HT active layers with various morphologies were prepared via different fabrication processes, including a spin-coated thermal annealing process (namely, ST-P3HT), a spin-coated free-standing process (namely, SF-P3HT), and a drop-casted free-standing process (namely, DF-P3HT). These transistors were triggered by pulse voltage to mimic different synaptic functions. Upon single pulse action potential, all transistors could mimic typical excitatory postsynaptic current decay behavior. Upon pair and multipulse action potentials, the ST-P3HT-based transistor could mimic paired-pulse facilitation (PPF) and short-term potentiation, the SF-P3HT-based transistor could mimic paired-pulse depression and short-term depression, and the DF-P3HT-based transistor could mimic PPF and long-term potentiation, respectively. When the voltage pulse was activated at different gates, the transistors could mimic neuromodulation response and logic operation. The possible origins were discussed in terms of an electric double layer (EDL) model and the surface morphology and crystalline structure of the P3HT layer. EDL can enhance the P3HT active layer to accumulate hole carriers. The structural characteristics of the P3HT layer will affect the hole transportation efficiency, thus affecting the transient output current of the transistors. Lastly, we demonstrated that P3HT-based OTFTs can function as good synaptic transistors with diversified modes.

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