Biomolecules for nanodevice applications

Abstract

The density of devices needs to be integrated into various systems increases with the advancement in technology. In order to integrate high density of devices, smaller feature size down to nanometer level has to be achieved. With the current technology, copper may no longer be suitable as interconnect material due to the increase in resistance as the size of the interconnect shrinks and there is an increasing need to explore new materials with novel electron transport properties. Many work has been done on the optical interconnects and the carbon nanotube interconnects as alternatives to the conventional copper interconnects. However, both of these areas have their own limitations.

In this dissertation, peptides are explored as an alternative. The electrical properties of these peptides will be tested, discussed and evaluated with the aim to use the peptides as future interconnects. The main motivation for the use of peptides as an alternative for interconnect arises from the fact that peptides can be readily self assembled in solution onto silicon wafer or any other substrates by controlling the surface chemistry. Self assembly is a fast and cheap process to create interconnects. The peptides will have specific covalent bonding to the substrate unlike carbon nanotube interconnects. In addition, peptide forms atomically precise chain length and the length of the peptide can be varied by changing the number of monomer repeats. The peptides can consist of amino acids which have different functional groups for attachment to specific substrate. For example, cysteine would attach to gold, histidine to nickel and alanine to NH2 functionalized silicon. In this work on peptides, there are also cysteine and cysteine interaction between the neighbouring peptides, resulting in the formation of disulfide bond. This disulfide bond brings the self assembled peptides closer together forming a highly packed layer. The short distance between the self assembled short peptides resulted in conjugated phenyl rings that give rise to possible charge transportation.