CAREER: Mixed-bonded IV-VI semiconductors for hybrid heterostructures

职业：用于混合异质结构的混合键合 IV-VI 半导体

• 批准号: 1945321
• 负责人: Kunal Mukherjee
• 金额: $ 59.3万
• 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: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945321&HistoricalAwards=false
• 关键词: CAREER; Mixed; bonded; IV; VI

The nature of bonding between the atoms that make up any material sets the ultimate properties of that material. This is true for structural materials used in construction with critical mechanical properties as well as for electronic materials used in computers, solar cells, and energy efficient lighting. The bonding in common electronic materials such as silicon, germanium, and III-V semiconductors has certain limitations in the infrared, a part of the light spectrum invisible to our eyes but that new sensors can use to examine objects around us in unprecedented ways. This project focuses on exploring a different class of electronic materials known as IV-VI semiconductors, which have very unusual bonding. The researchers would like to understand how the peculiar bonding of the IV-VIs can be harnessed for better infrared devices. Here, the research team is adopting a hybrid approach to combine the unique strengths of IV-VI materials without losing the practical advantages of common, established electronic materials. Along this theme, the team is building visual education tools, lab demonstrations, and public understanding videos all to highlight the nature of atomic bonding and demonstrate how a few simple rules at the atomic scale lead to complex structures. These activities engage with students at the high school, undergraduate, and graduate levels, guided by an inclusive approach to scientific education and training.Mixed covalent-ionic bonding in IV-VI semiconductors offers opportunity for advancing optoelectronics in the underserved mid-infrared and terahertz domains. These materials have ultra-narrow direct band gaps, with unusual carrier transport and recombination properties that are favorable for efficient integrated infrared light emitters. The research team is integrating IV-VI semiconductors with covalently bonded III-V materials via heteroepitaxy. This offers the chance to take the mature technology platform offered by III-V systems and boost it with new abilities from the IV-VI materials and their respective heterovalent interfaces. This project evaluates if such hybrid heterostructures may help overcome limitations in conventional infrared heterostructures by (1) modulating traditionally fixed interfacial electronic properties using tunable heterovalency, (2) screening and slowing down minority carriers from recombining at dislocation defects in integrated devices, and (3) providing new optical properties within heterostructures via stable and metastable polymorphs with inverted band structures. The research team uses molecular beam epitaxy to synthesize pristine IV-VI/III-V films and interfaces and analyzes their structure by transmission electron microscopy, x-ray diffractometry, atom probe tomography, and electron channeling contrast imaging. Electrical and optical measurements in the mid-infrared on larger devices as well as at the individual defect level provide insight into how synthesis and structure connect with the properties of interest. Bonding of matter and the search for new electronic materials form the core pillars of the research in this project. The research team integrates these two themes into an education and outreach program comprising of developing a cost-effective teaching tool to understand bonding in matter, science teacher training, workforce development via research, industry interaction, and curriculum development for this generation of post-silicon students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

构成任何材料的原子之间的成键性质决定了这种材料的最终性质。这适用于建筑中使用的具有关键机械性能的结构材料，以及用于计算机、太阳能电池和节能照明的电子材料。硅、锗和III-V半导体等常见电子材料中的键合在红外方面有一定的限制，红外是我们眼睛看不见的光谱的一部分，但新的传感器可以用来以前所未有的方式检查我们周围的物体。这个项目的重点是探索一种不同类别的电子材料，即IV-VI半导体，这种材料具有非常不寻常的成键。研究人员想要了解如何利用IV-VIS的特殊结合来制造更好的红外设备。在这里，研究团队正在采用一种混合方法来结合IV-VI材料的独特优势，同时又不会失去常见的、成熟的电子材料的实用优势。围绕这一主题，该团队正在构建可视化教育工具、实验室演示和公众理解视频，所有这些都是为了强调原子键的性质，并演示原子尺度上的几个简单规则如何导致复杂的结构。这些活动在科学教育和培训的包容性方法的指导下，吸引了高中、本科生和研究生水平的学生。IV-VI半导体中的混合共价离子键为在服务不足的中红外和太赫兹领域推进光电子学提供了机会。这些材料具有超窄的直接带隙，具有不同寻常的载流子传输和复合特性，这有利于高效集成红外光发射器。该研究团队正在通过异质外延将IV-VI半导体与共价结合的III-V材料集成在一起。这提供了利用III-V系统提供的成熟技术平台并通过IV-VI材料及其各自的异价界面的新能力来提升它的机会。该项目评估了这种杂化异质结是否有助于克服传统红外异质结的局限性：(1)利用可调谐的异价态来调制传统固定的界面电子性质；(2)屏蔽和减缓集成器件中少数载流子在位错缺陷处的复合；(3)通过稳定和亚稳的具有倒置能带结构的多晶型在异质结中提供新的光学特性。该研究小组使用分子束外延来合成原始的IV-VI/III-V薄膜和界面，并通过透射电子显微镜、X射线衍射仪、原子探针断层扫描和电子沟道对比成像对其结构进行分析。在较大器件上的中红外以及在单个缺陷水平上的电学和光学测量提供了对合成和结构如何与感兴趣的特性相关联的洞察。物质的结合和寻找新的电子材料构成了这个项目研究的核心支柱。研究团队将这两个主题整合到教育和外展计划中，包括开发成本效益高的教学工具来了解物质联系、科学教师培训、通过研究、行业互动和为这一代后硅谷学生开发课程来发展劳动力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。