Structure and Properties of AlN and InN Surfaces and Defects

AlN 和 InN 表面的结构和性能及缺陷

• 批准号: 0906805
• 负责人: James Speck
• 金额: $ 45.28万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906805&HistoricalAwards=false
• 关键词: Structure; Properties; AlN; InN; Surfaces

Technical: Although nitride semiconductor materials are being used in some electronic and photonic applications including heterostructure field-effect transistors and blue light emitters, defects, impurities, and surface issues are hampering new applications such as the use of increasingly higher aluminum content AlGaN alloys for ultraviolet light emitting diodes and lasers and the development of InN-based transistors for terahertz emitters. This project aims to address these materials science issues through a tightly coupled experimental and computational effort. High quality AlN, InN, and their alloys are grow epitaxially and the high quality samples enable detailed characterization of surfaces, point defects, and impurities using structural, electrical, and optical techniques. Electron accumulation layers on the surface are investigated and controlled. The limits of n-type and p-type doping will be pushed. The experimental effort is directly tied to state-of-the-art first-principles calculations based on density functional theory; the "band-gap problem" will be addressed through the use of techniques that have recently successfully been implemented, such as quasi-particle calculations and hybrid functionals. Deep (localized) and shallow (extended) levels of defects and impurities are investigated, as well as surface reconstructions and surface states. Closing the loop between theoretical and experimental results is expected to provide deep understanding of fundamental atomic-level mechanisms and phenomena associated with synthesis and processing of these novel materials.Non-technical: This project addresses basic research issues in a topical area of materials science with high technological relevance. The wide-band-gap semiconductors that are the focus of the investigation are recognized as the prime materials for light emitters throughout the visible and into the ultraviolet, and the transition to solid-state lighting will have tremendous impact both in the developed as well as the developing world. Nitrides are also starting to gain ground in the area of high-frequency devices, with applications in telecommunications and radar. Another area of high potential impact is for photovoltaics, where the nitride materials systems can span the range from ultraviolet to infrared. This project has significant educational value: the graduate students are involved in a tight collaboration between theory and experiment. In addition, the computational project will make use of the brand new Allosphere facility at the California Nanosystems Institute at UCSB. The Allosphere is a 3-story-high spherical space in which a fully immersive and interactive virtual environment can be experienced. It will be helpful with the visualization and understanding of wave functions and bonding environments in the various materials, as well as with the dissemination of results to a broad audience.

技术支持：虽然氮化物半导体材料被用于一些电子和光子应用，包括异质结构场效应晶体管和蓝光发射器，但缺陷、杂质和表面问题阻碍了新的应用，例如使用越来越高的铝含量的AlGaN合金用于紫外发光二极管和激光器，以及开发用于太赫兹发射器的InN基晶体管。该项目旨在通过紧密耦合的实验和计算工作来解决这些材料科学问题。高质量的AlN，InN及其合金外延生长，高质量的样品可以使用结构，电学和光学技术详细表征表面，点缺陷和杂质。研究和控制了表面的电子积累层。n型和p型掺杂的极限将被推动。实验工作直接与基于密度泛函理论的最先进的第一性原理计算有关;“带隙问题”将通过使用最近成功实施的技术来解决，例如准粒子计算和混合泛函。深（本地化）和浅（扩展）的缺陷和杂质的水平进行了调查，以及表面重建和表面状态。理论和实验结果之间的闭环有望提供与这些新型材料的合成和加工相关的基本原子级机制和现象的深入理解。非技术性：本项目解决材料科学主题领域的基础研究问题，具有高技术相关性。作为研究重点的宽带隙半导体被认为是整个可见光和紫外线发光体的主要材料，向固态照明的过渡将对发达国家和发展中国家产生巨大影响。氮化物也开始在高频器件领域占据一席之地，并在电信和雷达中得到应用。另一个具有高潜在影响的领域是光化学，其中氮化物材料系统可以跨越从紫外到红外的范围。该项目具有重要的教育价值：研究生参与了理论和实验之间的紧密合作。此外，计算项目将利用UCSB加州纳米系统研究所全新的Allosphere设施。Allosphere是一个3层楼高的球形空间，在其中可以体验完全沉浸式和交互式的虚拟环境。这将有助于对各种材料中的波函数和键合环境的可视化和理解，以及将结果传播给广大受众。