International Postdoctoral Fellows Program: Mechanism of Fermi Level Pinning at Metal-Semiconductor Nanojunctions Fabricated by STM Tip

9505480同国际初级研究员和博士后研究员计划使美国科学家和工程师能够在国外进行为期3至24个月的研究。该项目的奖项提供了联合研究的机会，并提供了使用国外独特或互补的设施、专业知识和实验条件的机会。该奖项将支持威廉·M·童博士为期12个月的博士后研究访问，与保罗·佩尔菲蒂博士在意大利的Struttura della Materia研究所合作。这个方案的目标是制造原子尺度的金属-半导体导体结，并探索它们的电子结构与其尺寸和其他参数的函数关系。进行这些实验的工具是扫描隧道显微镜(STM)。大多数金属的小岛可以通过电场电离金属原子从经过处理的钨尖端沉积出来。用扫描隧道谱(STS)研究了这些结的电子结构，它本质上是岛的IV曲线。这项研究不仅可以探索纳米岛沉积的相对不带电区域，而且通过绘制态密度(DOS)随岛大小、局域缺陷、掺杂能级和其他因素的变化规律，还将有助于更好地理解近原子极限下的费米能级(FL)钉扎机制。***

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. ***