Molecular & Biomolecular Electronics

The analysis and control of single molecules both constitutes fundamental work and lies central to the development of derived molecular devices. A variety of transport and tunnelling methodologies are being used in analysing the electrical properties of individual macromolecules. Nanometre-scale circuits are being fabricated are methods developed whereby molecules can be manipulated, delivered to and analysed at such junctions.

Biomolecular Tunneling: A variety of ECSTM and conductive probe methodologies are being applied to the imaging of biological structure at up to 10 million times magnification under conditions approaching the physiological. Electroactive imaging probes can be used simultaneously to map out electron transfer/conductance characteristics of biological molecules. We are presently investigating the influence of environmental parameters, including temperature, on this imaging and our interpretation of the single molecule tunnelling profiles subsequently generated. It is possible to observe redox state dependent conductance switching and pressure-dependent phenomena with small metalloproteins.

Electrochemical fluid tunnelling images of surface assembled protein or enzyme adlayers can be acquired at molecular levels of resolution fairly routinely (above /above left). In modulating the alignment of electrode Fermi energy with redox accessible molecular DOS "transistor-type" switchable molecular conductance behaviour can be observed (below left) and correlated directly with redox switching (below right).