U.S.-Pakistan Cooperative Research: Growth and Characterization of Semiconductor and Magnetic Nanocrystals Using Buffer-Layer-Assisted Growth

0353419 weaver本项目支持伊利诺伊州厄巴纳市伊利诺伊大学材料科学与工程系John H. Weaver博士与巴基斯坦伊斯兰堡信息技术研究所Irshad Bhatti博士的合作研究项目。他们将使用缓冲层辅助生长（BLAG）来研究半导体和磁性纳米晶体的生长和表征。最近发展起来的技术在合成新型量子结构方面具有巨大的潜力。它消除了生长颗粒和衬底之间的相互作用，因为衬底被一种稀有的气固多层缓冲。因此，纳米颗粒生长发生在稀有气体表面，而BLAG使得生长纳米尺寸的三维晶体和团簇成为可能。在这个项目中，BLAG将用于生长磁性和半导体纳米结构，其中尺寸分布可以改变，并且可以确定其结构，磁性和光学性质。世界各地的研究人员都在尝试合成纳米颗粒；计划中的方法是独特的，因为它允许生长几乎任何元素的纳米粒子和广泛的二元系统。生长是在真空中受控条件下进行的。电子状态表征包括扫描隧道显微镜，这样就可以一个接一个地询问粒子。pi将研究尺寸分布对物理性质的影响，团簇成核、生长和聚结的机制，以及团簇与衬底接触时的相互作用。一个具体的目标是阐明纳米颗粒的晶体结构作为磁性颗粒（Co, Fe）和半导体颗粒（Ge, Si）尺寸的函数。该项目的一个关键组成部分涉及美国和巴基斯坦研究生和本科生的教育和培训。这两个小组之间的交流是可能的，两国的学生都可以在另一个国家体验科学。联合项目将导致联合出版物和提供会议文件。重点突出的讲习班、研讨会、短期课程以及对更多机构的访问将丰富更广泛的社区。该计划的更广泛影响包括在巴基斯坦伊斯兰堡COMSATS信息技术研究所（CIIT）建立一个研究实验室。这将使巴基斯坦合作者能够在伊斯兰堡建立一个研究实验室，该实验室将包括BLAG的生长和所产生的纳米结构的光学表征。巴基斯坦的年轻科学家将亲身体验与纳米科学和技术相关的国际兴奋。韦弗博士和他的学生将通过咨询和参观来帮助建立实验室。巴基斯坦政府科技部（Ministry of Science and Technology， MOST）将支持CIIT的研究活动。

0353419 WeaverThis project supports a cooperative research project between Dr. John H. Weaver, Department of Materials Science and Engineering at the University of Illinois, Urbana, Illinois and Dr. Irshad Bhatti, Institute of Information Technology, Islamabad, Pakistan. They will study the growth and characterization of semiconductor and magnetic nanocrystals using buffer-layer-assisted growth (BLAG). The recently developed technique has tremendous potential for the synthesis of novel quantum structures. It eliminates the interaction between growing particles and the substrate because the substrate is buffered by a rare gas solid multilayer. Thus, nanoparticle growth occurs on the rare gas surface, and BLAG makes it possible to grow three-dimensional crystals and clusters of nanometer dimensions. In this project, BLAG would be used to grow magnetic and semiconducting nanostructures where the size distributions could be varied and their structural, magnetic, and optical properties could be determined. Researchers worldwide are trying to synthesize nanoparticles; and the planned approach is unique because it allows growing nanoparticles of almost any element and a wide range of binary systems. Growth is done in vacuo under controlled conditions. Electronic state characterization includes scanning tunneling microscopy so that the particles can be interrogated, one by one. The PIs will study the effect of size distributions on the physical properties, the mechanisms of cluster nucleation, growth, and coalescence, and the interactions of the clusters when they come into contact with the substrate. A specific goal is to elucidate the crystal structure of the nanoparticles as a function of size for magnetic particles (Co, Fe) and semiconducting particles (Ge, Si).A key component of this project involves the education and training of U.S. and Pakistani graduate and undergraduate students. Exchanges would be possible between the two groups, with students from both nations able to experience science in another country. Joint projects would lead to joint publications and contributed conference papers. Focused workshops, seminars, short courses, and visits to a larger set of institutions would enrich a broader community. A broader impact of this program involves the development of a research laboratory at the COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan. This would enable the Pakistani collaborator to set up a research laboratory in Islamabad that would include BLAG growth and optical characterization of the nanostructures produced. The young scientists in Pakistan would experience first-hand the international excitement associated with nanoscience and technology. Dr. Weaver and his students would help to establish the laboratory through advice and visits. The Ministry of Science and Technology (MOST), Government of Pakistan, will support the research activities at CIIT.