Nanoscale Examination of Electronic States in Molecular and Atomic Wires

Princeton University, Princeton NJ

Investigators

Abstract

This project uses atomic-scale engineering to produces materials for the study of one-dimensional electronic states. Because of their simplicity and uniformity, carbon nanotubes and related nanoscopic peapod structures offer unique advantages for controlled experiments. Other one-dimensional structures are based on atomic wires fabricated by self-assembly of atomic adsorbates or by direct manipulation of single atoms on a surface. Scanning tunneling microscopy (STM) will be used to directly visualize, and locally characterize and modify matter on the scale of single atoms and molecules. The electronic states will be studied in order to address issues relevant to the development of molecular and atomic-scale electronic devices. The detailed structural and transport studies will help develop more accurate theoretical models needed to understand the general problem of correlation among electrons in complex coupled systems. The project combines technologically relevant research in nanoscale science with investigations of fundamental problems at the forefront of condensed matter physics. Until the basic electronic properties of nanostructures can be reproducibly measured and understood, applications will not be realized for molecule-based electronic, biological, or chemical devices. The project integrates research and education-in the technical training of students who carry out the experiments, in the development of a undergraduate curricula in nanoelectronics, and in outreach presentations of nanoscience and technology to future students and the general public. The project will investigate the electronic properties of novel wires, so-called single-walled-nanotubes (SWNTs), that are so small that it would take 40,000,000 laying side-by-side to span a dime. In such tiny wires, the electrons are forced to flow in essentially one direction, in one-dimension only. In ordinary wires, electrons actually move in three directions, while drifting in a single direction between battery terminals. The SWNTs are be self-organized and grown on surfaces so that their electronic properties are accessible for experimental studies. Understanding and manipulating the electronic states of these tiny structures may enable technological advances in nanotechnology and provide fundamental understanding of the exotic nature of correlated electron systems. Cutting-edge experimental techniques developed at the intersection of physics, materials science, and nanotechnology should provide the building blocks for future generations of electronic devices or biosensors. The project integrates research and education-in the technical training of students who carry out the experiments, in the development of a undergraduate curricula in nanoelectronics, and in outreach presentations of nanoscience and technology to future students and the general public.