在過去的幾年中，DNA生物聚合物已用於各式各樣的元件中，其中有許多關於電阻式記憶體元件的研究應用。在這項研究中，我們探討將DNA生物聚合物用於突觸記憶元件的方法。首先在第一部分中，我們呈現在各種不同的製作條件下的元件性能，其中包括溶劑選擇，試劑濃度調整和塗佈的轉速調整。對元件施加驅動脈衝，對元件的電性進行量測分析，以確定最佳製作元件的條件。當對元件施加脈衝，元件的電阻率會有相對應的增強和抑制，並表現出良好的操作穩定性。接著在研究的第二部分中，我們進一步探究元件於突觸反應的一些重要測試，包括尖峰時間依賴可塑性（STDP）和成對脈衝促進作用（PPF）。通過施加不同數量的脈衝來探討脈衝數量與元件電阻率的關係，我們發現電阻率的維持與施加到元件上的脈衝數量相關，此特性可以模仿大腦中短期記憶轉向長期記憶的過程。這些研究結果展示了DNA生物材料於突觸記憶體元件具之可行性，可進一步發展生物材料於類神經網路之應用。

In the past years, DNA biopolymer has been used in a variety of devices and many demonstrations are reported in the application of resistive memory devices. In this study, we explored the employment of DNA biopolymer for synaptic memory elements. In the first part, we presented the device performance with respect to various fabrication conditions, including solvent selection, concentration of reagents, and coating parameters. Then, the electrical properties of the device, under various settings of driving pulses were characterized to determine the optimized operation conditions. The enhancement and suppression of device resistivity under the application of series of pulses were demonstrated with a good operation stability. In the second part of the study, we further presented measurement results for some important characters of synaptic responses, including spike-timing-dependent plasticity (STDP) and paired- pulse facilitation (PPF). The retention property was examined by applying different numbers of pulses and we show that the retention was correlated with the number of pulses applied to the device, mimicking well the transition process of short-term memory to long-term memory in our brain .Our study reveals that DNA biomaterials may be a promising candidate for synaptic device applications, paving the way towards further development of biomaterial-based neuromorphic circuit.

致謝 II
摘要 III
Abstract IV
目錄 V
圖目錄 VIII
表目錄 XI

第一章 緒論 1
1.1 前言 1
1.2 DNA簡介與應用 2
1.3 電阻式記憶體簡介 3
1.3.1. 電阻式記憶體發展 3
1.3.2. 電阻式記憶體運作機制 5
1.3.3. 有機電阻式記憶體 8
1.4 突觸元件介紹 8
1.4.1 突觸元件種類 8
1.4.2 突觸可塑性 11
1.4.3 突觸元件應用 12
1.5 研究動機 15

第二章 實驗方法 16
2.1 材料製作 16
2.1.1 DNA-CTMA合成 16
2.2 元件製作 17
2.3 量測儀器 19

第三章 突觸元件電性探討 22
3.1. 電阻對時間的變化 22
3.1.1. 不同溶劑對於形成DNA-CTMA薄膜造成電阻變化的影響 22
3.1.2. 不同DNA-CTMA薄膜厚度造成電阻變化的影響 24
3.1.3. 最佳化參數元件的電阻變化探討 26
3.2. 脈衝對元件電阻的影響 28
3.2.1. 脈衝持續時間(Ton)對於元件電阻變化的影響 28
3.2.3. 脈衝大小對於元件電阻變化 31
3.3. 元件增強和抑制表現(Potentiation and Depression) 31
3.4. 結論 33

第四章 突觸元件仿生之探討 34
4.1. 峰值時間依賴可塑性(STDP) 34
4.2. 成對脈衝刺激(PPF) 36
4.3. 短期記憶到長期記憶的轉換(STM to LTM) 37
4.4. 結論 40

第五章 結論與未來期許 41
參考文獻 42

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