双分子膜间非碳体系二维单晶超薄膜的可控制备及其性质研究

Metal and semiconductor nanomembranes (NMs) are monocrystalline structure with thickness of less than one hundred nanometer and with minimum lateral dimension at least two orders of magnitude larger than the thickness. Due to the nature of high anisotropy, NMs offer many features that cannot be reproduced in other material formats. They are of central importance to a rapidly expanding frontier in nanoscience and nanotechnology. Graphene, as a member of carbon family, has been well investigated and its novel physical phenomena arising from its unique atomic 2D geometry have been shown promising towards a wide variety of applications. However, metal and semiconductor nanomembranes in a nanometer or even atomic thickness are still greatly underdeveloped. "Top-down" approach is popularly used in making semiconductor devices. But this approach is limited by a strict and complicated preparation condition, huge facilities, and substrate support. In contrast, wet process via "bottom-up" approach is more favorable for production in large scale, ease of post-functionalization and operation. .In this proposal, we utilize a bimolecular membrane which gives a lamellar structure in solution as template for synthesis of metal and semiconductor nanomembranes through a solution process. The bimolecular membrane possesses the nature of liquid crystal. In an optimal condition, the bimolecular membrane could form an order bimolecular membrane/water layer/bimolecular membrane sandwich structure. The thickness of water layer could be tuned from several to hundreds of nanometers when adjusting the mass ratio of amphiphilic molecules and water. When a reaction for forming metal and semiconductor is introduced into the two-dimensional space of water layer, a nanomembrane with tuned thickness would be expected. We will study systematically the process and mechanism of the growth of metal and semiconductor nanomembranes. By combing experimental results and theoretical simulation, we will investigate the physical properties of nanomembranes, such as electrical property, optical property, FET, and optoelectronic property, etc. and try to understand the relationship of structure and property. This work will provide the possibility for creating various non-carbon 2D crystalline nanomembranes and exploring basic studies of 2D physics and developing new device integration.

单晶超薄膜是厚度在纳米尺度、横向尺寸在宏观范围的二维单晶材料，其高度各向异性的结构使其表现出不同于体相材料的纳米物性，正在引起广泛关注。获得纳米级甚至原子级可控厚度的金属和半导体类单晶超薄膜是纳米材料领域的重要研究方向，同时也是巨大的挑战。目前对石墨烯等碳体系单晶超薄膜结构与性质的研究较为深入，但由于制备方法的限制，对非碳体系单晶超薄膜的结构与性质研究还处于起步阶段。本研究拟利用液晶双分子膜为模板体系、液晶双分子膜间的空间作为反应场，获得典型金属和半导体单晶超薄膜。通过调控双分子膜体系的组装结构，以期实现对单晶超薄膜晶面和厚度的有效控制。研究单晶超薄膜结构与性质的关系。通过本项目的实施，扩展非碳二维单晶超薄膜体系，开发二维纳米材料的新物性，为二维单晶膜材料的研究和应用提供更丰富的实验依据。

单晶超薄膜是厚度在纳米尺度、横向尺寸在宏观范围的二维单晶材料，其高度各向异性的结构使其表现出不同于体相材料的纳米物性受到广泛关注。获得纳米级甚至原子级可控厚度的金属和半导体类单晶超薄膜是纳米材料领域的重要研究方向，同时也是巨大的挑战。目前对石墨烯等碳体系单晶超薄膜结构与性质的研究较为深入，但由于制备方法的限制，对非碳体系单晶超薄膜的结构与性质研究还处于起步阶段。本项目研究致力于非层状结构二维单晶纳米材料的精准可控制备，制备厚度可控、结构规整的非层状结构二维单晶超薄膜仍是巨大的挑战。项目研究团队提出了利用二维限域反应制备大面积二维单晶体的新方法，利用可精确调控层间距的液晶双分子膜间的水层、纳米结构限域空间作为反应场，制备具有纳米级/原子级厚度、大面积的金属、半导体和有机分子二维单晶材料，通过物理剥离及化学合成的方法制备基于层状化合物的二维单晶薄膜材料，并研究了其新颖的电学、光学、催化及分离等理化性质。为非常规二维单晶材料的制备提供了普适可行的方法和途径，为进一步理解其结构与性质的关系提供了理论和实验支持。