Contacting organic molecules by metal evaporation

Reproducible electrical contacts to organic molecules are created non-destructively by indirect electron beam evaporation of Pd onto molecular films on cooled substrates. In contrast, directly evaporated contacts damage the molecules seriously. Our conclusions are based on correlating trends in properties of a series of molecules with systematically varying, exposed functional groups, with trends in the electrical behaviour of Pd/molecule/GaAs junctions, where these same molecules are part of the junctions.