We are currently working towards incorporating a single molecule as the functioning part of a field effect transistor (FET) device. Using an FET as the experimental apparatus provides the ability to directly measure electronic and vibrational structure through inelastic electron tunneling spectroscopy and through the effect of a capacitively coupled gate electrode.
   Molecules earmarked for characterization include metalloporphyrin assemblies and a synthetic 4-helix peptide bundle with biological or non-biological cofactors. Amino acid residues on the helices can be designed to incorporate various cofactors such as metalloporphyrin or iron-containing photosynthetic complexes like those found in cytochromes and the entire molecule can be designed so that the cofactors reside in different locations and act as sites for electron localization within the protein medium. Designer molecules are useful models for learning about real biological systems such as electron-transfer enzymes. Additionally, single molecules are candidates for novel electronic devices incorporating molecular transistors.
 

Nanogaps used for single molecule electrical contact

Synthetic peptide candidate for single molecule electronic measurements