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標題: | 高環境穩定性之多功能元件在全透明與
可撓曲電子上的應用 Environmentally Stable, Multi-Functional Device for Transparent and Flexible Electronics |
作者: | Po-Kang Yang 楊伯康 |
指導教授: | 吳志毅(Chin-I Wu) |
關鍵字: | 全透明與可撓式電子,電阻式記憶體,嚴苛環境,表面效應,奈米摩擦發電機,可拉伸電子元件,摺紙技術., transparent & flexible electronics,resistive random access memory,harsh environments,surface effects,triboelectric nanogenerator,stretchable electronics,origami., |
出版年 : | 2015 |
學位: | 博士 |
摘要: | 本論文中我們將分別有四個主題來討論針對可撓曲與全透明系統來設計所需要的記憶體與發電元件。
在第二章中,我們首先利用石墨烯做為氧化鋅全透明電阻式記憶體 (ZnO TRRAM) 之透明電極與表面鈍化層來減低表面氧氣吸附對於ZnO TRRAM電阻轉換特性的影響。由於石墨烯薄膜在可見光波段的高穿透率,以及其可作為表面氣體阻隔層之特性,我們不僅維持了ZnO TRRAM整體的高透光性,更大大改善了ZnO TRRAM在不同氣體氛圍下之轉換穩定性與提供了石墨烯未來可應用的方向。 在第三章中,由於氧化鉿 (HfO2) 薄膜同時具有寬能隙、高介電性常數以及對於環境氧氣吸附之低靈敏特性,加上其已在電阻式記憶體領域之關鍵角色。我們成功製作出以HfO2為基底之全透明電阻式記憶體 (HfO2 TRRAM)。相較於傳統氧化鋅之電阻式記憶體,HfO2 TRRAM不僅維持了高透光率、良好的轉換特性,更重要的是對於環境中氧氣吸附並不敏感。此外,HfO2本身亦同時具有高抗酸蝕與抗輻射等特性,HfO2 TRRAM在經由蟻酸 (formic acid) 浸泡與質子 (能量: 2 MeV、劑量: 1015 cm-2) 轟擊之後,皆仍能維持穩定之操作特性,提供了全透明記憶元件以作為太空或是高輻射等嚴酷環境下應用之契機。 在第四章,我們完成了以origami-摺紙技術應用於奈米摩擦發電機的首例。其主要原理是採集環境機械能量,藉由靜電以及摩擦起電的方式,將機械能轉換成電力輸出。此種摺紙發電機不僅容易製造且可應用於多元型態,更兼具重量輕,成本低,以及可回收等優點。而利用此種發電方式所產生的電輸出已被用於直接點亮商用的LED 燈。另外,有鑑於其發電特性與外界施加之機械應力有成比關係,此種摺紙發電機也可作為自供電壓力感測器 (Self-powered sensors)。 在第五章,我們成功利用波浪狀的Kapton薄膜與可伸展性的PDMS基板結合成可隨意撓曲與伸展之奈米摩擦發電機。相較於傳統的摩擦發電機系統,我們所製作的發電機具能提供不同操作模式下的發電效果,包含了壓縮與拉伸模式。此外,此種發電機能用於曲面上來發電,並且不隨曲面取率的變化,而輸出減小。最重要的是,利用此種發電機可拉伸之特性,使其能被用於即時感測多種人體的運動,從關節變化甚至到皮膚表層的移動皆能被檢測。 This thesis consists of an introduction, four chapters and a conclusion, with each chapter covering a different topic. In the introduction, we introduce the various limitations and constrants of the conventional resistive random access memories and power sources that we study in the later chapters. In chapter 2, we report a ZnO-based transparent resistance random access memory (TRRAM) employing atomic layered graphene exhibiting not only excellent transparency (less than 2% absorptance by graphene) but also reversible resistive switching characteristics. The statistical analysis including cycle-to-cycle and cell-to-cell tests for almost 100 cells shows that graphene plays a significant role to suppress the surface effect, giving rise to the notable increase in the switching yield and the insensitivity to the environmental atmosphere. The resistance variation of high resistance state of ZnO is greatly suppressed by covering graphene as well. The device reliability investigation, such as the endurance more than 102 cycles and the retention time longer than 104 sec, reveals the robust passivation of graphene for TRRAM applications. The obtained insights show guidelines not only for TRRAM device design and optimization against the undesired switching parameter variations but also for developing practically useful applications of graphene. In chapter 3, a fully transparent resistive memory (TRRAM) based on Hafnium oxide (HfO2) with excellent transparency, resistive switching capability, and environmental stability is demonstrated. The retention time measured at 85 °C is over 3×104 sec, and no significant degradation is observed in 130 cycling test. Compared with ZnO TRRAM, HfO2 TRRAM shows reliable performance under harsh conditions, such as high oxygen partial pressure, high moisture (relative humidity = 90% at 85 °C), corrosive agent exposure, and proton irradiation. Moreover, HfO2 TRRAM fabricated in cross-bar array structures manifests the feasibility of future high density memory applications. These findings not only pave the way for future TRRAM design, but also demonstrate the promising applicability of HfO2 TRRAM for harsh environments. In chapter 4, we present the first origami triboelectric nanogenerators (TENGs) using paper as the starting material, with high degree of flexibility, light weight, low cost, and recyclability. Slinky and doodlebug shape TENGs can be easily fabricated by properly folding printer papers. The as-fabricated TENGs are capable of harvesting ambient mechanical energy from various kinds of human motions, such as stretching, lifting, and twisting. The generated electric outputs have been used to directly light up commercial LEDs. In addition, the as-fabricated TENGs can also serve as self-powered pressure sensors. In chapter 5, we present a flexible triboelectric nanogenerator (FTENG) based on wavy-structured Kapton film and serpentine electrode on the stretchable substrates. The as-fabricated FTENG is capable of harvesting ambient mechanical energy via both compressive and stretching modes. Moreover, the FTENG can be a bendable power source to work on curved surfaces. Furthermore, the FTENG can be adaptively attached onto human skins for monitoring gentle body motions. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/54714 |
全文授權: | 有償授權 |
顯示於系所單位: | 光電工程學研究所 |
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