CAREER: Minority Carrier Transport in Wide Bandgap Semiconductor Nanowires: Classical and Quantum Size Effects

技术：本项目主要研究宽带隙半导体纳米线的少数载流子输运特性。少数载流子输运具有特殊的意义和重要性，因为它控制着许多设备中的多数载流子输运，并且对载流子-载流子相互作用也很敏感。本课题采用气-液-固生长法合成了尺寸可控的独立式宽禁带半导体纳米线。一维少数载流子输运，特别是表面依赖和非表面依赖的少数载流子扩散长度和漂移迁移率，研究了基于扫描探针显微镜的新型技术，该技术具有集成的电和光学探测能力。通过不同表面条件下表面电子结构之间的关系以及表面作为少数载流子复合和散射中心的影响，研究了经典的尺寸效应。量子尺寸效应通过由各种传输限制机制控制的少数载流子迁移率的大小（直径）依赖性来检验，这些机制包括载流子-杂质、载流子-声子和载流子-载流子（少数-多数）散射过程。非技术：该项目涉及材料科学主题领域的基础研究问题，具有高技术相关性。随着载流子输运在广泛的电子和光电子应用中的重要性，该项目的成功将为潜在的变革纳米材料和器件工程工作提供基础。该项目将为PI未来的努力奠定基础，通过尺寸、表面和杂质工程，开发调整电子、声子、光子、杂质和表面之间相互作用的方法，以实现对纳米级材料的光学、电学、磁学和热电性质的综合控制。该项目的研究部分已纳入多方面的教育和推广活动。除了为本科生和研究生提供研究培训外，该项目还旨在加强不同背景学生的普通本科物理教育，并为华盛顿州立大学物理专业本科生提供“重点概念”实验室体验。该项目的外联部分旨在为科学教师的教育和专业发展提供持续、长期的支持。

Technical: This project is to study minority carrier transport properties in nanowires made of wide-bandgap semiconductors. Minority carrier transport is of special interest and importance, as it controls majority carrier transport in many devices and is also sensitive to carrier-carrier interactions. In this project, free-standing wide-bandgap semiconductor nanowires with controlled dimensions are synthesized using the vapor-liquid-solid growth method. One-dimensional minority carrier transport, specifically the surface-dependent and -independent minority carrier diffusion lengths and drift mobilities, is studied using novel scanning probe microscopy-based techniques with integrated electrical and optical probing capabilities. The classical size effects are investigated via the correlation between surface electronic structures under various surface conditions and effects of surfaces as minority carrier recombination and scattering centers. The quantum size effects are examined via the size (diameter) dependence of the minority carrier mobility controlled by various transport-limiting mechanisms including carrier-impurity, carrier-phonon, and carrier-carrier (minority-majority) scattering processes.Non-technical: The project addresses basic research issues in a topical area of materials science with high technological relevance. With the importance of carrier transport in wide-ranging electronic and optoelectronic applications, the success of this project will provide a fundamental basis for the potentially transformative nanoscale materials and device engineering efforts. This project will lay the foundation for future efforts by the PI to develop the approach of tuning the interplay among electrons, phonons, photons, impurities, and surfaces via dimension, surface, and impurity engineering in order to achieve an integrated control over optical, electrical, magnetic, and thermoelectric properties in nanoscale materials. The research component of this project is integrated into multifaceted educational and outreach activities. In addition to providing research training for students at both undergraduate and graduate levels, the educational efforts aim to enhance general undergraduate physics education for students with diverse backgrounds, as well as to provide a "focused concept" laboratory experience for undergraduate physics majors at the Washington State University. The outreach element of this project aims to provide continuing, long-term support for science teacher education and professional development.