9505480 Tong The International Junior Investigator and Postdoctoral Fellows Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twelve-month postdoctoral research visit by Dr. William M. Tong to work with Dr. Paolo Perfetti at the Instituto di Struttura della Materia in Italy. The goal of this proposal is to fabricate metal- semiconductor conductor junctions of atomic scale and probe their electronic structure as a function of their sizes and other parameters. The tool to perform these experiment is the scanning tunneling microscopy (STM). Small islands of most metals can be deposited by field ionizing metal atoms from a pretreated tungsten tip. The electronic structure of these junctions is investigated by scanning tunneling spectroscopy (STS), which is essentially the IV curve of the islands. This study will not only allow exploration of the relatively uncharged area of nano-island deposition, but it will also help gain a better understanding of the Fermi Level (FL) pinning mechanism in the near-atomic limit by mapping out how the density of states (DOS) evolves as a function of island size, local defects, dopant levels, and other factors. ***
