EAGER: Strain Engineering the Mechanical Properties of Black Phosphorus

有了这个探索性研究（EAGER）的早期概念资助，该团队将研究生产薄层磷的可行性，根据测量和理论预测，这种薄层磷比薄层碳具有更有吸引力的电子特性。由一个或几个原子薄层组成的超薄材料正在被研究作为目前硅基微电子的替代品。当受到变形时，薄层磷的电子特性会发生变化，可以通过施加外力来控制，当放置在柔性材料支撑上时，将提供有趣的设备功能。本项目将展示宏观和纳米尺度弯曲对磷薄膜电子性能的影响。能够生产和控制磷的特性将为电子产品带来新材料和新概念。研究原子薄层应变的实验-理论结合方法的见解将适用于其他二维材料。该研究项目整合了与西班牙裔专业工程师协会（Society of Hispanic Professional Engineers, Inc.）合作的学生招募和与太阳能汽车项目相关的公共教育的推广项目。本研究的目标是通过实验实现和表征与计算研究相结合来展示原子薄膜的应变工程。被称为黑磷的磷同素异形体的二维（2D）薄膜将被剥离到碳化硅和柔性衬底上。预计黑磷将以一种取决于磷层数和图案尺寸的方式符合碳化硅中的图案。对柔性基板施加一个力，黑磷就会产生张力。引入黑磷的应变将通过拉曼光谱和扫描隧道显微镜测量。图案的分层将通过原子力显微镜来测量。实验将以密度泛函理论为基础进行建模，以获得二维薄膜在纳米尺度上的机械和电子特性的图像。对应变的理解和控制将使具有带隙的新型各向异性二维电子材料成为可能，并将为在石墨烯以外的技术上重要的二维薄膜中实现应变工程建立一个强大的平台。

With this EArly-concept Grant for Exploratory Research (EAGER), the team will investigate the feasibility of producing thin layers of phosphorus that, based on measurements and theoretical predictions, have more attractive electronic properties than thin layers of carbon. Ultrathin materials that consist of one or a few atomically-thin layers are being studied as alternatives for current silicon-based microelectronics. The electronic properties of thin layers of phosphorous change when subjected to deformation, enabling control by the application of external forces that would offer interesting device functionality when placed on flexible material supports. This project will demonstrate the effect of macro- and nano-scale bending on the electronic properties of thin phosphorus films. Being able to produce and control the properties of phosphorous would enable new materials and concepts for electronics. Insight from the combined experimental-theoretical approach to investigate strain in atomically thin layers would be applicable to other two-dimensional materials. The research program is integrated with an outreach program involving student recruitment in partnership with the Society of Hispanic Professional Engineers, Inc. and public education in relation to the Solar Vehicle Project. The goal of this research is to demonstrate strain engineering in atomically-thin membranes by combining experimental realization and characterization with computational investigation. Two-dimensional (2D) films of the phosphorus allotrope known as black phosphorus will be exfoliated onto silicon carbide and flexible substrates. It is expected that the black phosphorus will conform to patterns in the silicon carbide in a manner that depends on the number of phosphorus layers and pattern dimensions. The black phosphorus will be strained by application of a force to the flexible substrate. The strain introduced in the black phosphorus will be measured by Raman spectroscopy and scanning tunneling microscopy. The delamination from the patterns will be measured by atomic force microscopy. The experiments will be modeled by density functional-based theory to obtain a picture of the mechanical and electronic properties at the nanoscale in two-dimensional films. The understanding and control of strain will enable a new anisotropic, 2D electronic material that has a bandgap, and will establish a robust platform for achieving strain engineering in technologically important 2D films beyond graphene.