Solution-Processed Ionically Polarized Oxide Dielectrics and Integrated Electronic Materials for Low-Voltage Transparent Transistors

技术摘要：该项目发展了一种变革性的想法，即以β-氧化铝钠(SBA)为例的快速离子导体可以在晶体管中充当高电容栅电介质。钠或其他小的无机阳离子被插入到Al(2-x)O_3(AlOx)的非化学计量比层之间。晶体管可以是溶液制造的，透明的，并可在电池电压(1-5V)下操作。它们可以使用具有更高载流子迁移率的有机半导体或无机氧化物半导体。虽然最终的技术目标是生产改进的电子电路，但这里总结的项目是揭示这种材料和相关电子氧化物材料中的基本固态结构和离子传输机制。这将通过以下方式完成：(A)揭示在其形成过程中从溶胶-凝胶前体穿过的详细的结构中间体，(B)研究导致高介电常数的依赖于阳离子的电场诱导的离子运动，以及(C)推断阳离子可能通过其从介电薄膜中迁移出来的机制，从而导致不必要的泄漏电流和晶体管的退化，目的是将这些影响降至最低。前两项任务将通过实验(合成、X射线衍射、扫描探针显微镜、频率相关介电测量)和理论(分子动力学)研究相结合的方式完成。第三项任务将部分地通过考虑将与BA集成的导体和半导体，评估阳离子可以渗透到这种材料中的可能性，并推导出使泄漏电流最小的条件来实现。因此，将致力于提炼这些伴生材料，包括新发现的Al-Zn-SnO导电组合物和氧化锌半导体。感谢材料研究部(DMR)陶瓷(CER)项目的支持。非技术总结本建议提出了一种变革性的想法，即基于一种名为β-氧化铝(SBA)的化合物的某种类型的陶瓷导电体可以在某些设备中充当电气绝缘体。虽然这项提案的工作将是揭示为什么SBA化合物在电子技术中如此有用的根本科学原因，但最终的影响将是极大地提高印刷、透明、电池供电的电路的能力，这些电路可以应用于显示器、光伏系统以及安装在挡风玻璃和窗户等透明基板上的传感器。这项工作还将导致高中和本科课堂模块，展示电子制造、物理和硅技术以外的应用的广泛可能性。这些模块将与资源有限的教育实验室中随时可用的仪器一起使用。该项目非常适合私人投资机构与包括霍华德大学和乔治王子社区学院在内的少数族裔机构正在进行的纳米材料合作，该合作已经培训了三名非裔美国人研究人员，这种合作将得到扩大。研究生和博士后研究员将接受模拟、材料合成、物理表征和电子集成技术的协同组合培训，这些技术可以应用于未来广泛的材料机会。感谢材料研究部陶瓷(CER)项目的支持。

TECHNICAL SUMMARY:This project develops the transformative idea that fast ionic conductors exemplified by sodium beta-alumina (SBA) can act as high-capacitance gate dielectrics in transistors. The sodium, or other small inorganic cation, is intercalated between nonstoichiometric layers of Al (2-x) O3 (AlOx). The transistors can be solution-fabricated, transparent, and operable at battery voltages (1-5 V). They can employ organic semiconductors or inorganic oxide semiconductors with higher carrier mobility. While the ultimate technological goal is to produce improved electronic circuits, the project summarized here is to uncover fundamental solid state structures and ion transport mechanisms in this and related electronic oxide materials. This will be done by (a) uncovering the detailed structural intermediates traversed during their formation from sol-gel precursors, (b) studying the cation-dependent electric-field-induced ionic motions that are responsible for the high dielectric constants, and (c) deducing mechanisms by which the cations could conceivably migrate out of the dielectric films, resulting in undesired leakage currents and degradation in transistors, and with the aim of minimizing these effects. The first two tasks will be accomplished through combined experimental (synthesis, X-ray diffraction, scanning probe microscopy, frequency-dependent dielectric measurements) and theoretical (molecular dynamics) study. The third task will be carried out in part by considering conductors and semiconductors with which the BAs will be integrated, evaluating the possibilities that cations could penetrate such materials, and deriving conditions under which leakage currents would be minimized. Effort will therefore be devoted toward refining these accompanying materials, including newly discovered Al-Zn-Sn-O conductive compositions and ZnO-based semiconductors. Support from the Ceramics (CER) program in the Division of Materials Research (DMR) is gratefully acknowledged.NON-TECHNICAL SUMMARYThis proposal develops the transformative idea that a certain class of ceramic electrical conductors based on a compound known as sodium beta-alumina (SBA), can act as electrical insulators in certain devices. While the work of this proposal will be to uncover the fundamental scientific reasons why the SBA compounds can be so useful in electronics technologies, the ultimate impact will be to greatly advance the capabilities of printed, transparent, battery-powered circuits that can be applied to displays, photovoltaic systems, and sensors mounted on transparent substrates such as windshields and windows. The work will also lead to high school and undergraduate classroom modules that demonstrate the broad possibilities of electronics fabrication, physics, and application beyond silicon technology. These modules will be usable with apparatus readily available in educational laboratories with limited resources. This project is a strong fit with an ongoing nanomaterials collaboration of the PIs with minority institutions including Howard University and Prince Georges Community College that has already trained three African-American researchers, and that collaboration will be expanded. Graduate students and postdoctoral fellows will be trained in a synergistic combination of simulation, materials synthesis, physical characterization, and electronic integration techniques that can be applied to a broad range of future materials opportunities. Support from the Ceramics (CER) program in the Division of Materials Research (DMR) is gratefully acknowledged.