Synthesis and applications of dispersible exfoliated metal oxide nanosheets fabricated by ALD

本研究针对气相低温无机和有机薄膜形成化学领域，以提高基本理解和推进工程系统应用。它将扩展在非晶和多晶薄膜的低温化学工艺领域的基础知识，特别是在低温原子层沉积（ALD）领域。原子层沉积利用气相前驱体在二元表面反应方案中建立薄膜厚度具有单层精度的无机薄膜。大多数ALD材料的应用，包括半导体逻辑器件中的商用高介电常数绝缘体，需要超过~2纳米的薄膜来实现功能性能。这项工作将强调ALD在可接受的低温衬底上的生长起始，并探索自粘表面可释放ALD薄膜的最终最小厚度限制。研究将寻求了解ALD过程中的表面反应机制和衬底相互作用，以生产可行的纳米层状半导体，这些半导体可以从衬底释放并悬浮在溶液中。PI还将探索这些材料的基本特性，并与由分层结构剥离形成的类似已知材料进行比较，并研究如何使用新方法和材料产生有益的影响。一个特别的应用重点将是各向异性材料的光电化学水解离。该项目将建立在以前的工作基础上，悬浮纳米片的工作将在ALD或薄膜沉积研究界目前尚未探索的领域启动新的研究。有几个具体的挑战，包括设计ALD集成方案和自粘超薄材料的工艺。剥离纳米片的研究领域非常新颖，其可能的结果也非常广泛，因此本研究中获得的基础知识将影响和扩展薄膜沉积反应的工程领域。更广泛的影响该项目将促进教学，允许高级研究生指导学士和更多的初级博士生在实验室工作。PI计划通过继续从代表性不足的群体中招收学生来扩大参与。这项新的研究将加强太阳能光电化学的知识和研究基础设施，这是北卡罗来纳州立大学和研究三角地区普遍关注的一个日益增长的领域。结果将由学生和PI在同行评议的期刊和研究会议上广泛传播。这项工作在经济太阳能驱动水电解的新材料加工方案中的可能结果可能在能源和环境方面对社会产生重大的有益影响。推进对超薄膜沉积的基本理解的计划也将影响广泛的领域，包括先进的电子、传感器技术和其他能源系统。

1034374ParsonsIntellectual MeritThis research addresses the field of vapor-phase low temperature inorganic and organic thin film formation chemistry, to improve fundamental understanding and advance engineered system applications. It will expand fundamental knowledge in the field of low temperature chemical processes for amorphous and polycrystalline thin films, particularly in the field of low temperature atomic layer deposition (ALD). Atomic layer deposition utilizes vapor phase precursors in a binary surface reaction scheme to build up inorganic thin films with monolayer precision in film thickness. Most ALD material applications, including for example commercial high dielectric constant insulators in semiconductor logic devices, require films in excess of ~2 nanometers to achieve functional performance. This work will emphasize ALD growth initiation on receptive low temperature substrates, and explore the ultimate minimum thickness limits for self-cohesive surface-releasable ALD thin films. Research will seek to understand surface reaction mechanisms and substrate interactions during ALD processes to produce viable nano-layered semiconductors that can be released from a substrate and suspended in solution. The PI will also explore the fundamental properties of these materials in comparison with similar known materials formed by layered structure exfoliation, and examine how the new methods and materials can be used for beneficial impact. A particular application focus will be on anisotropic materials for photoelectrochemical water dissociation. This project will build on previous work, and the work on suspended nanosheets will initiate new research in a field that is not currently explored in the ALD or thin film deposition research community. There are several specific challenges, including designing ALD integration schemes and processes for self-cohesive ultrathin materials. The area of exfoliated nanosheets is sufficiently new, and the possible outcomes are sufficiently broad that the fundamental knowledge gained in this study will impact and expand the field of engineering of thin film deposition reactions. Broader ImpactThe project will promote teaching by allowing senior graduate students to mentor BS and more junior PhD students working in the lab. The PI plans to broaden participation by continuing to recruit students from underrepresented groups. The new research will enhance knowledge and research infrastructure in solar photoelectrochemistry, which is a growing area of interest at NC State and in the Research Triangle region in general. Results will be broadly disseminated by the students and PI in peer-reviewed journals and research conferences. The possible outcome of this work in new material processing schemes for economical solar-driven water electrolysis could provide significant beneficial impact to society in terms of energy and environment. The plans to advance basic understanding of ultra-thin film deposition will also impact a wide variety of fields, including advanced electronics, sensor technologies and other energy systems.