Morphology and Chemsitry of Lateral Composition Modulations

本项目的目标是扩展对III-V族半导体合金系统中成分不均匀性的理解。该方法利用多种实验方法来研究多层膜中合金层的（非）均匀性和横向成分调制。研究的中心工具是一个组合的MBE-STM室，用于研究合金层中的原子尺度结构和多层膜中的横向成分调制。这些信息将反馈到生长过程中，并允许完善相分离区域的组装。具体目标是：定量地了解InGaAs的表面重构、应变和局部合金成分之间的关系;实验确定自发横向成分调制的引发机制及其与表面特征和局部合金成分变化的关系;在InGaSbAs合金中形成自组装阵列;建立经验性的自组装程度，可以实现使用图案化的基板。该研究预计将有重大影响的合金形成的基本物理理解和组成不均匀性的起源在III-V化合物半导体材料系统。结果将应用于消除器件层内的成分不均匀性。此外，该研究还为设计半导体薄膜的成分变化和开发其纳米尺度结构所产生的新特性（如低阈值激光器）奠定了基础。该项目解决了与电子/光子材料相关的基础研究问题，具有技术相关性，并强调研究和教育的整合。该项目促进教学，培训和各级科学掌握的学习，从博士后。研究人员，研究生，非传统的本科生，和中学女生，包括研究人员从小学本科院校（弗林特大学）。该项目还将改善密歇根州的研究和教育基础设施。它已经建立了一个记录，包括来自代表性不足的群体，包括妇女，非洲裔美国人和西班牙裔的成员。PI将继续在建立研究团队方面寻求多样性。

The objective of this project is to extend understanding of the initiation of compositional inho-mogeneities in III-V semiconductor alloy systems. The approach utilizes a number of experimen-tal methods to examine the (non)homogeneity of alloy layers and lateral composition modulation in multilayers. A tool central to the investigation is a combined MBE-STM chamber to examine the atomic scale structure of clustering in alloy layers and lateral composition modulation in mul-tilayers. This information will feedback into the growth process and allow perfecting the assem-bly of the phase-separated regions. Specific goals are: To develop a quantitative understanding of the connections between surface reconstruction, strain, and local alloy composition for InGaAs; To determine experimentally the initiation mechanisms of spontaneous lateral composition modulation and how it relates to surface features and the local variations in alloy composition; To form self assembled arrays in InGaSbAs alloys; To establish empirically the degree of self-assembly that can be achieved using patterned substrates.The research is expected to have significant impact on basic physical understanding of alloy for-mation and origins of compositional inhomogeneities in III-V compound semiconductor material systems. The results will be applied to eliminate compositional nonuniformities within device layers. Additionally, the research forms the basis to design compositional variations in semicon-ductor thin films and exploit the novel properties arising from their nanometer-size scale struc-ture, such as low threshold lasers. %%% The project addresses fundamental research issues associated with electronic/photonic materials having technological relevance and emphasizes the integration of research and education. The project promotes teaching, training, and learning of all levels of scientific mastery, from post Ph.D. researchers, to graduate students, nontraditional undergraduates, and middle-school girls, including researchers from Primarily Undergraduate Institutions (University of Michigan-Flint). The project will also improve the research and education infrastructure in Michigan. It has al-ready established a track record for including members from underrepresented groups, including women, African Americans, and Hispanics. The PIs will continue to seek diversity in building their research team.***