| 摘要: | 由於有機材料使電子產品具有可撓性、簡單製程和低成本的優勢，在最近幾年引起相當大的注意。有機記憶體是一個必要的元件，在邏輯元件的操作上負責提供資料或儲存資料，例如：無線射頻辨識標籤、電子紙和電子看板。有機記憶體在結構上大致可分為雙穩態兩端元件和電晶體型式的三端元件。比較這兩種結構，雙穩態兩端元件的優點在於只需要較低的操作電壓和相對簡單的製程。在第二章中，我們利用金奈米粒子摻雜在聚合物裡面形成雙穩態有機記憶體。當提供外部電壓給有機記憶體時，元件特性可從低導電狀態轉變為高導電狀態和得到一個急遽上升的傳輸電流。我們在此提出空間電荷侷限電流來解釋傳導機制，並透過理論和實驗來驗證傳導機制。在第三章中，我們提出一個新的概念，就是利用聚合物去連結金奈米粒子，並混合在聚合物裡面作為記憶體之主動層。透過穿遂電子顯微鏡的分析，證實金奈米粒子可均勻地分散在聚合物裡面。這使元件能有更高的穩定性，並且利用外部電壓能夠精準控制這元件雙穩態之特性，使元件可操作次數 (endurance) 達到上千次和保持時間 (retention time) 超過三天。在第四章中，我們是首位在塑膠基板上，做出16-byte 可定址有機非揮發性記憶體陣列。記憶體開關次數可以超過上千次和預估可達到一年的保持時間。其元件在彎曲半徑為5 mm時，電性操作上仍然很穩定，並且可以透過外部電路去控制元件的操作，卻只需要消耗很低的功率。在第五章中，我們為了避免記憶體陣列產生誤動作，在有機記憶體上搭配一個有機二極體，這可使記憶體陣列能夠正確被讀取並能減少周邊的外部電路。此外，金奈米粒子顯示紫外光的吸收，所以我們利用紫外光的照射來清除記憶體之內容，因此二極體開關記憶體陣列能夠正確的被讀取和寫入，並能透過紫外光來重新清除記憶體之內容。因此，搭配紫外光清除的二極體開關記憶體陣列能夠扮演印製式電子開發的關鍵角色。 In recent year, organic materials have attracted much attention due to their potential advantages of flexibility, simple process and low cost. Organic memory is an essential device for any electronic logic system to provide or store information for the logic operation, such as radio-frequency identification (RFID)-tags, electronic-papers, and electronic-signage, which strongly demand for a low cost and simple process. The organic memory devices are basically characterized by two types of structure: two terminal bistable and three terminal transistor-like memory devices. The two terminal bistable memory devices offer the advantages of a low operation voltage and a simple process over three terminal transistor-like devices. In chapter 2, we utilize gold nanoparticles embedded polymer to fabricate bistable organic memory. The I–V characteristics show that the device switches from initial OFF-state to ON-state upon application of external electric field. The current transition exhibits in a very narrow voltage range causing an abrupt increase of the current. The conduction mechanism in nanoparticles contained polymer memory was investigated experimentally and theoretically. A trap-filled space-charge-limited current model is proposed to explain the transport mechanism in this memory device. In chapter 3, we get a stable organic bistable nonvolatile memory (ONBM) by using polymer chain stabilized gold nanoparticles (Au-NPs) in a host polymer as the memory active layer. The TEM images show that the polymer stabilized Au-NPs are well-dispersed in the polymer matrix. We further demonstrate our concept that is feasible for polymer stabilized Au-NPs. This concept enables Au-NPs to be well dispersed in host polymer in order to fabricate the stable devices. This concept enables Au-NPs to be well dispersed in host polymer in order to fabricate the stable devices. The electrical bistability of the device can be precisely controlled by applying a positive voltage pulse or a negative voltage pulse, respectively. This memory can be switched on and off over 1000 times without appreciable performance degradation. In addition, the memory state can retain over 3 days in air environment. In the chapter 4, a 16-byte addressable ONBM array on the plastic substrate has demonstrated. The memory cell can be switched on and off over 1,000 times and the longest retention time can be estimated to be nearly one year in the air. In the analysis of the mechanical flexibility, we demonstrated that electrical properties of our ONBM were fairly stable during the application of compressive stress down to 5 mm in bending radius. After connecting the ONBM array to the current-sensing circuit, the ONBM array can be correctly addressed and operated, while maintaining low-power consumption. To our best knowledge, this is the first actively addressable ONBM array ever demonstrated. In the chapter 5, we demonstrate an UV erasable stacked diode-switch organic nonvolatile bistable memory using a polymer-chain stabilized Au nanoparticles on the plastic substrate in the ambient air. The specified DS-ONBM array can be correctly read and avoided crosstalk in a much simplified peripheral circuits. The absorption spectrum of the gold nanoparticles shows ultra-violet (UV) absorption. Therefore, UV light was used to erase data in the DS-ONBM. The function of UV-erasing and diode-switch could greatly simplify the required peripheral circuits. This DS-ONBM was demonstrated to be able to read, write and retain the data and was reusable by UV light illumination. Hence, the UV-erasable DS-ONBM was fully applicable for key applications in printed electronics such as RFID tags. |
