脫氧核醣核酸 (Deoxyribonucleic acid, DNA) 為一種天然、有機、無害的材料，在科學領域上已經被廣泛運用，而改質後的 DNA 生物高分子薄膜具有製程簡單、可撓性、可見光波段的高穿透性等優勢，已經被運用於各式光電元件中。但是有機高分子材料因其複雜的堆疊結構，在原子間共振、分子間共振亦或電子傳遞方式等皆會對元件的表現產生影響。因此 DNA 生物高分子複合物於元件中所扮演的角色更需要被探討，然而目前對 DNA 生物高分子複合物於光電導元件相關研究有在許多方面仍有待釐清，例如電子-電洞對形成、載子傳遞、載子再複合等。
在本研究中我們即以 DNA 生物高分子複合物作為主要材料，建構出簡易三明治結構的元件，研究其光反應性質。首先，我們透過改變照射光的波長、施加偏壓、照光功率等探討元件的表現，並且以相對電流變化量與響應率方式統計，從統計結果中發現波長愈短，元件響應愈大。同時也透過對元件照射 UV 光與紫光時的光電流對光功率擬合，發現元件在照射這兩種光源時可能存在不同機制，我們以能隙間存在連續陷阱與單分子再複合解釋實驗結果。另一方面，使用不同電極材料做比較，發現 DNA 生物高分子複合物與金屬接面會有介面偶極效應產生。之後我們討論元件響應可能的來源，並透過摻雜銀奈米粒子或是改變電極鍍率等方式探討其結果。最後，我們對元件進行了穩定性討論。

Deoxyribonucleic acid (DNA), a natural, organic and harmless material, has been widely used in a lot of fields. DNA-based biopolymer films demonstrated in many kinds of optoelectronic devices, have several advantages, including ease of fabrication, flexible and high transmittance in the visible region. On the other hand, the complex behaviors of organic materials, including interatomic resonance, intermolecular resonance or charge transportation in organic materials play crucial roles on the electrical and optical properties of devices. For reasons outlined above, it is of great importance to understand the role of DNA biopolymer composites in optoelectronic devices. However, there is still lack of in-depth investigation on the generation of electron-hole pairs, charge transportation and charge recombination properties of devices base on DNA biopolymer composites.
In this study, we employed a simple sandwich structure based on DNA biopolymer composites to investigate the photoreponsive properties. In the first part of this study, we analyzed the optoelectronic properties through change the excitation wavelength, applied biases and intensity of incident light. The results were evaluated by normalized photoinduced current and responsivity, which showed that higher photoresponses were achieved with a shorter wavelength of light. Meanwhile, we fitted the photocurrent of the device with respect to optical power when irradiated by UV and violet light. The performance was explained by two mechanisms, which are related to continuous distribution of trapping centers and monomolecular recombination. The interfacial dipole at the biopolymer-metal interface could also be observed when changing the electrode materials. Based on the measurement results, we discussed possible origins of photocurrent and further studied the performance by doping silver nanoparticles (Ag NPs) and varying the deposition rate of electrode. Lastly, we performed a reliability test of the device and discussed the results.

第一章 緒論 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 DNA 介紹 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 DNA 與 DNA 複合材料 . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.2 DNA 與 DNA 複合材料於光電領域的應用 . . . . . . . . . . . . 2
1.2 材料電性 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2.1 DNA 載子傳導 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.2 金屬與介電材料薄膜介面 . . . . . . . . . . . . . . . . . . . . . . 6
1.2.2.1 金屬與半導體接觸 . . . . . . . . . . . . . . . . . . . . . 7
1.2.2.2 金屬與有機半導體接觸 . . . . . . . . . . . . . . . . . . 11
1.2.2.3 金屬與介電薄膜載子傳導機制 . . . . . . . . . . . . . . 13
1.3 研究動機 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
第二章 實驗方法 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1 DNA-CTMA 奈米複合材料備製 . . . . . . . . . . . . . . . . . . . . . . 15
2.1.1 DNA 材料準備 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.2 DNA-CTMA 高分子材料合成 . . . . . . . . . . . . . . . . . . . . 16
2.2 光電導元件製作 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3 特性量測儀器與量測方式 . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.1 膜厚分析 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.2 光學吸收量測 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.3 光功率量測 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.4 電性分析 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
第三章 實驗結果與討論 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.1 ITO/DNA-CTMA/Ag 三明治結構光電導元件電性 . . . . . . . . . . . . 22
3.1.1 光電導特性 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.1.2 波長對元件影響 . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.1.3 電場對元件影響 . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1.4 光功率對元件影響 . . . . . . . . . . . . . . . . . . . . . . . . . . 27
第四章 元件機制討論與驗證 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.1 光電流產生機制 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.1.1 DNA-CTMA 與銀奈米粒子交互作用的激子解離 . . . . . . . . . 33
4.2 載子傳遞機制 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.2.1 金屬與半導體接面 . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.2.2 載子於元件的載子傳遞 . . . . . . . . . . . . . . . . . . . . . . . 39
4.3 穩定性測試 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
第五章 結果與未來展望 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
參考文獻 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

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