CAREER: Tailoring the Surface State Conduction in Semiconductor and Topological Insulator Nanowires

这一职业奖由材料研究部的电子和光子材料计划(EPM)和凝聚态物理计划(CMP)联合资助。技术：由于纳米材料的表面体积比无处不在，表面和界面效应对其电子和光电性能至关重要。该职业奖的研究部分集中在砷化铟和铋化合物(例如，硒化铋或碲化铋)纳米线、传统III-V半导体的两个模型系统以及最近发现的拓扑绝缘体中的表面态导电的基础研究和控制。在传统的半导体纳米线中，表面态通常会降低材料的性能，而且往往是不受欢迎的。然而，对于拓扑绝缘体来说，拓扑表面态是基础研究和潜在器件应用都感兴趣的主题，因此应该防止体态，因为体态一直阻碍着拓扑表面态研究的进展。在本研究项目中，我们利用表面功能化、掺杂和异质结构材料设计来实验地调整半导体和拓扑绝缘体纳米线的表面导电性。这些对表面的材料和合成控制得到了电导和电容光谱的进一步补充，用于定量了解和评估纳米线的表面和整体传输。非技术：纳米线已经成为现代纳米电子学和光子学中的重要材料平台。由于纳米材料具有很高的表面积体积比，表面效应可能会主导整体的电学性质，并对材料的性能产生很大的影响。这一职业项目旨在实现对传统半导体或最近发现的拓扑绝缘体材料的纳米线中电子表面态的全面了解和精确控制。预计这些研究活动将使纳米材料发挥重要作用的多个领域受益。通过这个职业项目，PI还寻求在凯斯西储大学建立一个与研究项目相结合的教育项目。研究生和本科生都积极参与这个项目，学习最先进的纳米科学和技术。此外，克利夫兰地区的大学预科学生正通过与当地一所女子学校和一所市中心的学校合作进行外展，100%的学生获得补贴午餐。这些外展工作旨在激发青年学生将科学技术作为未来职业的兴趣和热情。该项目的进一步教育和推广工作包括开发一个非专业人员级别的互动网页和与研究活动有关的纳米科学课程/讲座。

This CAREER award is jointly funded by the Electronic and Photonic Materials Program (EPM) and Condensed Matter Physics Program (CMP), both in the Division of Materials Research.Technical: Due to the ubiquitously large surface-to-volume ratio of nanomaterials, surface and interface effects are essential to their electronic and optoelectronic properties. The research component of this CAREER award focuses on the fundamental study and control of surface state conduction in nanowires of indium arsenide and bismuth compounds (e.g., bismuth selenide or telluride), two model systems of the conventional III-V semiconductors and the recently discovered topological insulators. In conventional semiconductor nanowires, surface states generally degrade the material's performance and are often undesirable. However, for topological insulators, the topological surface states are the subject of interest for both basic research and potential device applications, and thus should be protected against the bulk states, which have been hindering the progress in the topological surface state research. In this research project, surface functionalization, doping and heterostructured material design are employed experimentally to tailor the surface conduction in semiconductor and topological insulator nanowires. These material and synthetic controls of the surface are further complemented by the conductance and capacitance spectroscopy for the quantitative understanding and evaluation of the surface versus bulk transport in nanowiresNon-technical: Nanowires have become an important material platform in modern nanoelectronics and photonics. Since nanomaterials have very high surface to volume ratio, surface effects could dominate the overall electronic properties and greatly impact the material performance. This CAREER project aims to achieve a comprehensive understanding of and precise control over the electronic surface states in nanowires of either conventional semiconductor or the recently discovered topological insulator materials. The research activities are expected to benefit multiple areas in which nanomaterials are playing an essential role. With this CAREER project, the PI also seeks to establish an education program integrated with the research project at Case Western Reserve University. Both graduate and undergraduate students engage actively in the project and learn state-of-the-art nanoscience and technology. In addition, pre-college students in the Cleveland area are being outreached through collaborations with a local girls' school and an inner city school with 100 percent of students receiving subsidized lunches. These outreach efforts are made to stimulate young students' interest and enthusiasm in pursuing science and technology as a future career. Further education and outreach endeavor of this project includes the development of a layman-level interactive web page and nanoscience course/lecture development related to the research activity.