Electronic Properties of Strained Narrow-Gap Quantum Wells

应变窄带隙量子阱的电子特性

• 批准号: 9973167
• 负责人: Michael Santos
• 金额: $ 35万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9973167&HistoricalAwards=false
• 关键词: Electronic; Properties; Strained; Narrow; Gap

This project addresses materials science and physics of 2DES(two dimensional electronic systems) based on InSb/AlInSb heterostructures. InSb is characterized by extreme values compared to other III-V materials, having the smallest energy gap, the smallest electron effective mass, the largest electron g-factor, and the most non-parabolic conduction band of all III-V semiconductors. These dramatically different parameters make two-dimensional electronic systems (2DESs) in InSb intriguing alternatives to GaAs-based 2DESs. Although the host material can influence the physics of the imbedded 2DES, there has been little motivation to study 2DESs in alternative materials since most are of considerably worse crystalline quality. Now that InSb/AlxIn1-xSb structures have been produced with mobilities comparable to those of GaAs/AlxGa1-xAs structures in which the fractional quantum Hall effect was first observed. These high mobilities, coupled with the vastly different parameter space of InSb 2DESs, provide the impetus for this project. The objectives are to advance the materials science of InSb/AlxIn1-xSb heteroepitaxy and to explore the properties of InSb 2DESs via low-temperature magneto-transport and magneto-optics.Several approaches will be used to improve materials quality. A scanning probe microscope, connected to the same vacuum as the MBE chamber, will be used to assess doping efficiency and buffer layer effectiveness on lattice-mismatched substrates. An atomic hydrogen source will be used to passivate the growth surface and facilitate oxide desorption from InSb substrates. Improvement of the materials quality will increase the relative importance of electron-electron interactions in 2DESs studied at low temperature. Magneto-transport experiments will explore the quantum Hall state to insulator transition and behavior in the fractional quantum Hall regime. Magneto-optical studies will be used characterize the energy band structure of InSb to determine the confinement potential through measurement of interband excitonic transitions in undoped wells; establish the two-dimensional band structure through analysis of excitonic transitions, intersubband resonance, and cyclotron resonance; and probe electron dynamics at low Landau-level fillings. The wide scope of the project requires collaboration between three co-investigators with collective expertise in molecular beam epitaxy, magneto-transport experiments, and optical measurements. %%%The project addresses basic research issues in a topical area of materials science having high potential technological relevance. The research will contribute basic materials science knowledge at a fundamental level to new aspects of electronic devices. A variety of fundamental issues are to be addressed in these investigations, and the proposed experiments may also develop technologically important material combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***

该项目涉及基于INSB/ALINSB异质结构的2DE（二维电子系统）的材料科学和物理。 INSB的特征是与其他III-V材料相比，具有最小的能隙，最小的电子有效质量，最大的电子G因子和所有III-V半导体的最非寄生虫传导带。这些急剧不同的参数在基于GAAS的2件的有趣替代方案中构成了二维电子系统（2DES）。尽管宿主材料可以影响嵌入的2DE的物理学，但是在替代材料中研究2DS的动力很少，因为大多数晶体质量较差。现在，INSB/alxin1-XSB结构已经产生，其迁移率与GAAS/alxga1-XAS结构相当的迁移率首先首先观察到了分数量子HALL效应。这些较高的迁移率，再加上INSB 2DES的参数空间截然不同，为该项目提供了动力。这些目标是推进INSB/Alxin1-XSB杂质杂质的材料科学，并通过低温磁通磁通和磁磁性探索INSB 2DESS的性质。将使用几个角度方法来提高材料质量。与MBE室相同的真空连接的扫描探针显微镜将用于评估对晶格不匹配的底物的掺杂效率和缓冲层的效率。原子氢源将用于奴役生长表面并促进INSB底物的氧化物解吸。材料质量的改善将增加在低温下研究的2DESS中电子相互作用的相对重要性。 Magneto-Transport实验将探索分数量子霍尔制度中的绝缘体转变和行为的量子霍尔状态。将使用磁光学研究来表征INSB的能带结构，以通过测量未息井中的带状兴奋子跃迁来确定限制电位。通过分析激发型转变，间间的共振和回旋子共振来建立二维带结构；和低兰道级填充物的探测电子动力学。该项目的广泛范围需要在分子束外延，磁通型传输实验和光学测量方面具有集体专业知识的三个共同投资者之间的合作。 %%％该项目解决了具有很高潜在技术相关性的材料科学主题领域的基础研究问题。该研究将在基本层面上为电子设备的新方面提供基础材料的知识。这些调查将解决各种基本问题，并且提出的实验也可能开发出技术上重要的材料组合。 该计划的一个重要特征是通过培训学生在根本和技术意义上的领域中培训研究和教育。 ***