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

该CAREER奖由材料研究部的电子和光子材料计划（Electronic and Photonic Materials Program，简称EMPs）和凝聚态物理计划（Condensed Matter Physics Program，简称CMP）共同资助。技术：由于纳米材料普遍具有大的表面积与体积比，表面和界面效应对其电子和光电性能至关重要。该CAREER奖的研究部分侧重于砷化铟和铋化合物纳米线中表面态传导的基础研究和控制（例如，硒化铋或碲化铋）、常规III-V族半导体的两个模型系统和最近发现的拓扑绝缘体。在传统的半导体纳米线中，表面态通常会降低材料的性能，并且通常是不期望的。然而，对于拓扑绝缘体，拓扑表面态是基础研究和潜在的器件应用的感兴趣的主题，因此应该被保护免受体态的影响，体态一直阻碍着拓扑表面态研究的进展。在本研究计画中，利用表面官能化、掺杂及异质结构材料设计等方法，来调整半导体及拓扑绝缘体奈米线的表面导电性。这些材料和表面的合成控制进一步补充了电导和电容光谱，用于定量理解和评估材料中的表面与体传输非技术：纳米线已成为现代纳米电子学和光子学中的重要材料平台。由于纳米材料具有非常高的表面积与体积比，表面效应可能主导整体电子特性并极大地影响材料性能。这个CAREER项目旨在全面了解和精确控制传统半导体或最近发现的拓扑绝缘体材料纳米线中的电子表面状态。预计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还寻求建立一个与凯斯西储大学的研究项目相结合的教育计划。研究生和本科生都积极参与该项目，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在通过与当地一所女子学校和一所内城学校的合作进行外联，100%的学生接受补贴午餐。这些外展工作是为了激发青年学生的兴趣和热情，把科学和技术作为未来的职业。该项目的进一步教育和推广奋进包括开发一个外行级别的互动网页和与研究活动相关的纳米科学课程/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.