Nanophysics
Henje Simmonds does some sample manipulation in the Omicron UHV, variable-temperature scanning probe microscope.
Mechanical, chemical and electronic device dimensions are constantly being made smaller - towards the nanometer scale. Our research is aimed at an understanding of the physics that underpins future molecular nanotechnology, with a strong emphasis on nano-scale molecular electronics.
Over the last few years we have made nm-scale electrical measurements using a Veeco atomic force microscope (AFM). Recently, using an Omicron UHV variable-temperature system, we have started investigating conduction in single molecules between electrodes, focusing on porphyrins, which are the active molecules in photosynthesis. The long-term goal is, with collaborators in chemistry and biosciences, to design single molecules (or molecular assemblies) that can be made sufficiently complex to integrate more than one device function.
Another related strand is to investigate the weak supramolecular interactions which are fundamental to self-assembly of functional molecular complexes, particularly in solution. For weakly bound adsorbed molecules, scanning probe microscopy (SPM) imaging suffers degradation of resolution. More drastically, the scanning tip can cause the molecules to diffuse or desorb from the surface. We are progressively developing surface x-ray diffraction techniques towards probing very weak supramolecular bonds in molecular arrays at surfaces under solution in order to access bonding regimes too weak for SPM approaches.
We are also pursuing scanning probe methods to study quantum dot and 2D electron systems.