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

技术：该项目是研究由宽带隙半导体制成的纳米线中的少数载流子传输特性。少数载流子输运具有特殊的兴趣和重要性，因为它控制许多器件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。本计画利用气-液-固生长法，合成尺寸可控的宽禁带半导体奈米线。一维少数载流子输运，特别是表面依赖和独立的少数载流子扩散长度和漂移迁移率，研究了使用新的扫描探针显微镜为基础的技术与集成的电气和光学探测能力。经典的尺寸效应进行了研究，通过在各种表面条件下的表面电子结构和表面作为少数载流子复合和散射中心的影响之间的相关性。量子尺寸效应通过尺寸（直径）依赖的少数载流子迁移率控制的各种传输限制机制，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processes.Non-technical：该项目解决了材料科学的一个热门领域的基础研究问题，具有很高的技术相关性。由于载流子输运在广泛的电子和光电应用中的重要性，该项目的成功将为潜在的变革性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，以开发通过尺寸，表面和杂质工程调整电子，声子，光子，杂质和表面之间相互作用的方法，以实现对纳米材料中光，电，磁和热电性能的综合控制。该项目的研究部分被纳入多方面的教育和外联活动。除了为本科生和研究生提供研究培训外，教育工作旨在加强对不同背景学生的普通本科物理教育，并为华盛顿州立大学的本科物理专业提供“重点概念”实验室体验。该项目的外联部分旨在为科学教师教育和专业发展提供持续的长期支持。

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.