Controlling Electron Transfer Through Single Molecules
Abstract
We have accomplished both tasks stated above and are ready for the next step-building a prototype molecular device based on single molecules. For the first task, we have developed a novel electrochemical technique to fabricate nanoelectrodes separated with an appropriate gap for molecular connection. It starts with a thin metal wire coated with an insulation layer except for a small portion near the center (Fig. 1a), and then etches the center portion electrochemically while monitoring the current through the wire (Fig. lb). As the diameter of the center portion decreases to the electron wavelength (a few A), the conductance becomes quantized and an atomically thin wire is formed. Further etching away the last few atoms produces a pair of nanoelectrodes separated with a small gap, and the ballistic transport responsible for the conductance quantization is replaced by quantum tunneling across the gap (Fig. 1c). As we shall show below, the tunneling current is also quantized because of the discrete nature of atoms, which can be used to control the gap width with atomic precision. Once a pair of nanoelectrodes with an appropriate gap is formed, we then bridge the gap with molecules by electrochemical deposition (Fig. 1d). In order to quickly fabricate a large array of the nanoelectrodes, we are currently testing a self-terminated method in collaboration with Motorola. We carried out the second task using conducting polymers as a model system. Conducting polymers are attractive electronic materials for a number of reasons.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2001
- Accession Number
- ADA403548
Entities
People
- Nongjian Tao
Organizations
- Florida International University