CAREER: Nanoscale Composition Control and Characterization of One-Dimensional Semiconductor Nanostructures

这个职业项目的主要目标是：(1)通过电子和磁性掺杂控制成分调制半导体纳米线的电子和磁性；(2)使用原子探针显微镜绘制具有单原子灵敏度和亚纳米分辨率的掺杂纳米线和纳米线异质结构的组成图；(3)利用阴极发光显微镜和扫描探针技术探索一维半导体纳米线主体中掺杂剂独特的局部电子和磁性特征；以及(4)将扫描探针显微镜与电传输测量相结合，以将单个电子和磁性掺杂原子的局部性质和分布与单个半导体纳米线的新颖的电、光和磁性质联系起来。其方法是首先通过无机合成建立半导体纳米线中受控掺杂的物理极限；然后展示单个纳米线的新的全局电子和磁性是如何从一维主体材料中掺杂原子和异质界面的局部性质产生的，例如，研究一维系统中改变的屏蔽长度如何影响纳米线同质结和异质结的电子性质。此外，还将探索具有一维态密度的巡回载流子介导的磁性掺杂原子的自旋有序化。对纳米材料的理解、表征和控制的实现有望推动纳米材料的科学和技术。%该项目致力于具有技术相关性的电子/光子材料科学的基础研究问题。该项目涉及化学、物理、工程和材料科学等多个学科，具有很强的潜在技术相关性。预计该项目还将加强研究和教育的基础设施。外联工作，包括针对任职人数不足的群体和女大学生的研究经验，是计划开展的活动的组成部分。在本科课程范围内，正在开发一门课程，将实验室研究经验纳入纳米尺度表面表征课程，以在具有战略重要性的领域培训未来劳动力。此外，PI还与芝加哥公立学校系统中接触到不同学生群体的不同高中教师群体合作。他的目标是为大芝加哥地区和其他地区的所有学生创造更多机会，让他们受益于西北大学的广泛资源。*

The primary objectives of this CAREER project are: (1) control of electronic and magnetic properties of compositionally modulated semiconductor nanowires via electronic and magnetic doping; (2) ability to map the composition of doped nanowires and nanowire heterostructures with single atom sensitivity and sub-nanometer resolution using atom-probe microscopy; (3) to explore unique local electronic and magnetic characteristics of dopants in one-dimensional semiconductor nanowire hosts using catholuminescence microscopy and scanning probe techniques; and (4) to combine scanning probe microscopy with electrical transport measurements to relate local properties and distribution of individual electronic and magnetic dopant atoms to novel electrical, optical, and magnetic properties of individual semiconductor nanowires. The approach is to first establish the physical limits of controlled doping in semiconductor nanowires through inorganic synthesis; to then demonstrate how novel global electronic and magnetic properties of a single nanowire arise from local properties of dopant atoms and heterointerfaces in a one-dimensional host material, examining, for example, how altered screening lengths in 1-d systems affect electronic properties of nanowire homojunctions and heterojunctions. Additionally, spin ordering of magnetic dopant atoms mediated by itinerant carriers with a 1-d density of states will be explored. Nanomaterials understanding, characterization, and control achieved are expected to advance the science and technology of nanomaterials.%%% The project addresses fundamental research issues in electronic/photonic materials science having technological relevance. The project is interdisciplinary involving chemistry, physics, engineering and materials science, and has strong potential technological relevance. The project is also expected to enhance the infrastructure for research and education. Outreach efforts, including research experiences for under-represented groups and women from female colleges, are an integral part of the planned activities. Within the undergraduate curriculum, a course is being developed that will integrate laboratory research experience into a course on nanoscale surface characterization to train members of the future workforce in an area of strategic importance. Additionally, the PI works with a diverse group of high school teachers that reach a diverse student population in the Chicago Public School system. It is his goal to create more opportunities for all students in the greater Chicago area and beyond to benefit from the broad resources at Northwestern University.***