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Title: | 多功能光電記憶元件 Multifunctional Photoelectrical Memory Devices |
Authors: | Yi-Rou Liou 劉怡柔 |
Advisor: | 陳永芳 |
Keyword: | 可變電阻式記憶體,多重量子井結構發光二極體,發光記憶體,光通訊,多層級光學記憶體,石墨烯,非晶態氧化銦鎵鋅,聚(3-己基?吩), resistance random access memory (RRAM),multiple quantum wells light emitting diode (MQWs LED),light emitting memory (LEM),optical communication,multi-level optical memory,graphene,amorphous InGaZnO (a-IGZO),poly(3-hexylthiophene) (P3HT), |
Publication Year : | 2018 |
Degree: | 博士 |
Abstract: | 在這個資訊時代,記憶體等相關的存儲設備在物聯網(IoT)、雲端網路和大數據工程的下一代趨勢中,扮演著舉足輕重的光電元件之角色。與電子系統相比,光子系統更具備有高頻寬,低功耗以及高通訊速度的優越特性,而這推動了光記憶體的發展。在本論文中,我們設計並展示了幾種基於半導體和奈米材料之複合材料的光記憶體,相信我們在這裡展示的方法可以作為光通訊發展的關鍵一步,相應的結果被歸類為三個主題,總結如下。
1. 高效能發光記憶體:可藉由光及電性揭示訊號的多功能元件 我們設計、製造並演示了雙穩態發光記憶體(LEM),使其編碼訊號能夠同時用光學及電學的方式去讀取,藉以克服常規記憶體陣列中,訊號在元件之間一個接著一個傳遞的電讀取方式所造成的最大數據傳輸量的限制。為了說明我們的工作原理,樣品結構組成是由石墨烯/二氧化矽/銀奈米顆粒/鋁摻雜氧化鋅的透明可變電阻式記憶體(RRAM)與氮化物半導體多重量子井結構的發光二極體(MQWs LED)串聯在一起,與傳統的可變電阻式記憶體相比,發光記憶體的訊號傳輸不會受到訊號延遲和讀取速度的限制。因此,這種新型元件有機會可以取代傳統的基於電子閱讀的通訊方式,還能很輕易地與現今的顯示科技結合在一起,也為光通訊元件的發展開闢了一條途徑,並擴展了傳統存儲設備的功能。 2. 可光寫入和光電可讀取的長期非揮發記憶體 光學記憶體對於高速、低成本資訊科技的未來發展至關重要,然而目前的光學記憶體仍然受限於元件尺寸難以微縮、沒有閘極控制下的短期非揮發性,而在閘極控制下維持記錄訊號會造成額外的耗能,為了克服這些挑戰,在此研究中,我們利用非晶態氧化銦鎵鋅(a-IGZO)和石墨烯奈米碎片(GNSs)複合材料中具有能保持長期壽命的持久光電導率(PPC)的特性,結合氮化物半導體多重量子井結構的發光二極體(MQWs LED),設計並展示了長期非揮發光學記憶體,用於記錄光學信號並且以電學和光學方式讀取編碼信號(平行讀出過程),為資訊通訊開闢了一條有用的路徑,並改善傳統電記憶體陣列中最大數據傳輸量的限制。因此,此研究可以為光電元件在資訊通訊的未來應用中提供替代的範例。 3.有機材料和石墨烯異質結構的可撓性光轉換記憶體:多層級非揮發光存儲的新平台 具有長期非揮發性質、高速度和低耗能成本的光學記憶體之發展對於未來的資訊時代至關重要。然而目前基於相變材料的光記憶體存在光讀出破壞性過程,耗能和短期非揮發性存儲的問題,除此之外,對於先前所報導的光記憶體來說,要做成適用於可穿戴設備和人工智慧應用上的可撓性元件是較難達成。為了克服這些挑戰性的問題並允許與可撓性基板整合在一起,我們在此研究中設計和展示了,基於石墨烯奈米薄片(GNFs)/聚(3-己基噻吩)(P3HT)複合材料以及石墨烯傳輸層的可撓性光轉換多層級長期非揮發記憶體。此種復合式元件結合了每種材料的獨特性質,使得我們設計的光記憶體可以在0.5伏特的低工作電壓以及紫外光和綠色光照射下,擁有高達196個不同層級狀態、10,000秒以上的非揮發性、10,000次以上的機械彎曲穩定性。我們在這裡所展示的方法不僅為光記憶體的發展提供了一種替代的範例,相信在不久的將來也能輕易地與當前成熟技術相互結合用於實際應用。 Towards the era of information, memory devices play a pivotal optoelectronic component in next-generation trends of the internet of things (IoT), cloud networks, and big data engineering. That drives the development of optical memories with the superior features of high bandwidth, low power consumption, and high communication speeds comparing with electronic systems. In this thesis, we have designed and demonstrated several optical memories based on the composites of semiconductors and nanomaterials. It is believed that our approach shown here can serve as a key step for the development of optical communication. The corresponding results are classified as three main topics and summarized as follows. 1. High-Performance Light-Emitting Memories: Multifunctional Devices for Unveiling Information by Optical and Electrical Detection A bistable light emitting memory (LEM) has been designed, fabricated and demonstrated, which enables to read encoded information electrically and optically. This unique feature can overcome the great hurdle in the limitation of the maximum data throughput in the electrical reading of conventional memory array in serial sequence. To illustrate our working principle, transparent resistance random access memory (RRAM) consisting of graphene/SiO2/Ag nanoparticles/Al-doped ZnO is deployed in tandem with light-emitting diode based on nitride semiconductor multiple quantum wells. Compared with conventional RRAM, the signal communication of LEM does not suffer from the interconnect delay and the limited reading speed. Therefore, this new device has the potential in replacing traditional communication based on electrical reading. In addition, it can be easily integrated with current display technologies. It opens up a route for the realization of optical communication devices and extends the functionality of conventional memory devices. 2. Optically writable and photo-electrically readable long-term non-volatile memories Optical memories are vitally important for the future development of high speed and low cost information technologies. However, the current optical memories still suffer from difficulty in scaling-down of size, and short-term non-volatility without the control of gate electrode, which results in an additional power consumption to maintain the encoded signal. To circumvent these challenge issues and achieve an all-optical-communication memory, here, a robust and long-term non-volatile optical memory is designed and demonstrated based on the integration of the composite of amorphous InGaZnO (a-IGZO) and graphene nanosheets (GNSs) with the long lasting lifetime of persistent photoconductivity (PPC) and nitride multiple quantum wells light-emitting diode (MQWs LED) for recording the signal optically and reading the encoded signal both electrically and optically (parallel readout process), which can open up an useful route for the information communication and improve the limitation of maximum data throughput in the conventional electrical memory array. The approach shown here therefore provides an alternative paradigm for the future application of optoelectronics device in information communication. 3. Flexible optical switching memory made with organics and graphene heterostructures: a new platform for multi-level non-volatile optical storage The development of optical memories with the attractive features of long-term non-volatility, high-speed, and low-energy-cost is vitally important for the future information age. However, the current optical memories based on phase-change materials are suffering from the problem of optical readout destructive process, energy-consumption and short-term non-volatile storage. In addition, flexible devices are greatly desirable for the application of wearable devices and smart artificial intelligence, which is still difficult to achieve for the reported optical memories. To overcome these challenge issues and allow the integration with flexible substrates, here, a flexible optical switching multi-level long-term non-volatile memory based on the composite of graphene nanoflakes (GNFs)/poly(3-hexylthiophene) (P3HT) and the transporting layer of graphene has been designed and demonstrated. Based on the integration of all unique properties of every constituent element in the composite device, it enables our designed optical memory with optically switchable memory states up to 196 distinct levels by UV and green light illumination under a low working bias of 0.5 V, a non-volatility over 10,000 sec, and a mechanical stability more than 10,000 bending cycles. Our approach shown here not only provides an alternative paradigm for the development of optical memory, but can also be easily integrated with currently mature technologies for practical application in the near future. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70039 |
DOI: | 10.6342/NTU201800391 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 物理學系 |
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ntu-107-1.pdf Restricted Access | 4.48 MB | Adobe PDF |
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