Nanometer-Scale Studies of Contacts to Nanowires, Advanced Oxide Films, and Molecular Layers

技术：本项目研究金属与半导体纳米线和薄膜在纳米尺度上的接触。要研究的系统包括(1)半导体纳米线的金属触点，(2)金属/复合氧化物/半导体结中高级氧化膜的金属触点，以及(3)金属/有机单层/半导体结中有机膜的金属触点。在电子器件中，接触对于电荷和自旋的注入至关重要，但在这些新兴材料中，对能带排列和微观输运过程的了解仍然很少。在本项目中使用了弹道电子发射显微镜（BEEM），内部光电发射光谱和三维静电建模，旨在对这些重要主题进行定量理解。该项目的重点是半导体纳米线的金属接触。肖特基势垒与纳米线的端对端接触。而更传统的一面呢？将使用BEEM研究接触几何形状，以确定纳米线能带与金属费米能（即肖特基势垒高度）的对齐如何取决于纳米线直径、金属功函数和纳米线周围的静电环境。非技术：该项目涉及材料科学的一个具有高技术相关性的主题领域的基础研究问题，并有望为半导体材料的金属接触提供新的科学理解，这是未来基于纳米线的电子器件发展所迫切需要的知识。该项目为研究生和本科生提供了高度跨学科和协作的培训，并为来自仅限本科院校的学生和教师提供了更多的研究机会。PI将继续积极参与课程发展，以便更好地将实验室实验、小组工作和解决问题整合到物理入门课程、科学推广、教师指导和旨在向中学生提供纳米技术信息和建议的推广活动中。

Technical: This project is to study metal contacts to semiconductor nanowires and thin films at the nanometer scale. The systems to be investigated include (1) metal contacts to semiconductor nanowires, (2) metal contacts to advanced oxide films in metal/complex oxide/semiconductor junctions, and (3) metal contacts to organic films in metal/organic-monolayer/semiconductor junctions. Contacts are critical for injection of charge and spin in electronic devices, but in these emerging materials the energy band alignments and microscopic transport process are still poorly understood. Ballistic electron emission microscopy (BEEM), internal photoemission spectroscopy, and three-dimensional electrostatic modeling are used in this project, aiming to obtain a quantitative understanding of these important topics. The emphasis of the project is on metal contacts to semiconductor nanowires. Schottky barrier contacts to nanowires in both the ?end-on? and the more conventional ?side? contact geometries will be studied using BEEM, in order to determine how the nanowire energy band alignment to the metal Fermi energy (i.e., the Schottky barrier height) depends on the nanowire diameter, on the metal work function, and on the electrostatic environment around the nanowires.Non-technical: The project addresses basic research issues in a topical area of materials science with high technological relevance, and is expected to provide new scientific understanding of metal contacts to semiconductor materials, a knowledge that is critically needed for the development of nanowire-based electronic devices of the future. This project provides highly interdisciplinary and collaborative training for graduate and undergraduate students and enhanced research opportunities for students and a faculty member from an undergraduate-only institution. The PI will continue active involvement with curriculum development to better integrate laboratory experiments, group work and problem solving into introductory physics courses, science outreach, teacher mentoring, and outreach activities aimed at providing information and advise about nanotechnology to middle school students.