Investigation of Nanoscale Electronic Properties and Transport in Semiconductors and Magnetic Materials

该项目致力于以III-V族氮化物异质结构和磁性材料中的自旋相关输运为中心的研究。该方法采用近端探针（扫描电容和隧道显微镜），以及一个导电的近端探针尖端进行局部光电导测量的局部电子结构和半导体和磁性材料中的电荷传输特性的表征。其目的是增加对缺陷和其他结构特征对材料性能和器件性能的性质和影响的理解，为各种器件应用的材料质量和外延层设计优化提供信息。磁性薄膜材料的研究将集中在自旋极化电流-电压和电导光谱的发展和应用，结合原子和磁力显微镜来表征磁性薄膜材料中的自旋极化电流注入和自旋相关载流子输运。该方法允许研究在长度尺度小到几十纳米的现象，如自旋极化电流注入到各种磁性和磁阻薄膜材料，自旋相关的载流子输运跨单磁畴壁，和详细的性质自旋相关的隧穿过程中的铁磁-绝缘体-铁磁隧道结。该项目解决了材料科学领域的基础研究问题，具有高度的技术相关性。高度优先将放在对研究生的先进纳米表征技术的现代材料和设备工程的重要性日益增加的培训。此外，将强调基本材料特性研究与其在器件工程和应用中的作用之间的联系，从而为学生提供与相关领域的其他大学和工业研究人员互动的机会。

This project addresses research centered on III-V nitride heterostructures and spin-dependent transport in magnetic materials. The approach employs proximal probes(scanning capacitance and tunneling microscopies), as well as a conducting proximal probe tip to perform local photoconductivity measurements for characterization of local electronic structure and charge transport properties in semiconductor and magnetic materials. The aim is to increase understanding of the nature and influence of defects and other structural features on material properties and device performance, serving to inform strategies for optimization of material quality and epitaxial layer design for a variety of device applications. Investigation of magnetic thin-film materials will focus on the development and application of spin-polarized current-voltage and conductance spectroscopy in combination with atomic and magnetic force microscopy to characterize spin-polarized current injection and spin-dependent carrier transport in magnetic thin-film materials. The approach allows studies at lengths scales as small as a few tens of nm of phenomena such as spin-polarized current injection into a variety of magnetic and magnetoresistive thin-film materials, spin-dependent carrier transport across single magnetic domain walls, and the detailed nature of spin-dependent tunneling processes in ferromagnet-insulator-ferromagnet tunnel junctions. %%%The project addresses basic research issues in topical areas of materials science with high technological relevance. High priority will be placed on training of graduate students in advanced nano-characterization techniques of increasing importance in modern materials and device engineering. In addition, the connection between studies of basic material properties and their role in device engineering and applications will be emphasized, thereby affording students opportunities for interaction with other university and industrial researchers working in related areas.***