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

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

0353419 Weaver This 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.