Scanning Tunneling Microscopy and Spectroscopy of Novel Silver-Containing DNA Molecules

The quest for a suitable molecule to pave the way to molecular nano-electronics¹ has been met with obstacles for over a decade^{2, 3}. Candidate molecules such as carbon nanotubes lack the appealing trait of self-assembly, while DNA seems to lack the desirable feature of conductivity⁴. Silver-containing poly(dG)-poly(dC) DNA (E-DNA) molecules were recently reported as promising candidates for molecular electronics⁵, owing to the selectivity of their metallization, their uniform structure, their resistance to deformation, and their most possible conductivity^{5, 6}. Here we present an elaborate temperature dependent high-resolution morphology characterization of these unique molecules, alongside a detailed depiction of their electronic level structure. Our findings⁷ were acquired by use of an ultra-high vacuum (UHV) scanning tunneling microscope (STM). The temperature dependence of E-DNA’s topographic features and density of states spurs intriguing insights. Moreover, the energy levels found for E-DNA indicate a novel, truly hybrid metal-molecule structure, potentially more conductive than its DNA-based peers.