| This dissertation work is focused on the study of two molecular electronic systems: (BETS)2GaCl4 and a Nanoscale Protein Molecular Wire. The detailed structural and electronic study of these systems was carried out using a custom built Ultra-High Vacuum Low Temperature Scanning Tunneling Microscope (UHV-LT-STM). The STM is capable of studying these systems with a spatial and energy resolution that has never been achieved before. lambda-(BETS) 2GaCl4 is a charge transfer superconductor in bulk crystals. Using a unique deposition procedure, a single sheet of the superconductor was formed on a Ag(111) metal surface. Molecular resolution imaging of the well ordered molecular layer revealed the exact arrangement of the molecules on the surface. The superconductivity of the layer was confirmed by scanning tunneling spectroscopy and spectroscopic mapping. The superconducting signal remained down to a chain of only four molecular pairs, which was only 3.5 nm long. The structure of the nanoscale protein molecular wire is revealed by high resolution STM imaging. Single proteins are imaged and individual amino acid side chains are resolved. Electronic and vibrational properties are explored using the spectroscopic capability of the STM. The STM images, in combination with high resolution vibrational spectroscopy, allow for the first direct sequencing of individual proteins. These two systems have unique properties that could be used as key components in the new class of Nano/Bio electronics. By developing a better understanding of the properties of these systems at the nanoscale, this PhD study answers questions about the electronic and structural properties of these systems and points towards their future electronic and bio-medical applications. |
