Electron beam lithography of two-component radical ion salt films: Reversible charge transfer in copper- and silver-TCNQ

The electron beam induced lithography process of radical ion salts of copper and silver tetracyanoquinodimethane (Cu(TCNQ)x and Ag(TCNQ)1 with x=1 and 2), gives direct access to microstructures of these organic conductors. The films are prepared in a vacuum chamber attached directly to a modified scanning electron microscope. They are obtained by a solid state reaction of subsequently deposited TCNQ and metal layers. Electrical measurements of wire structures have been performed in situ, showing a deviation from the expected resistance versus width relation when approaching the micron scale. Absorption spectroscopy of large irradiated areas is used to identify the process being a back-transformation of the salt into neutral TCNQ and suspended metal. The application of these microstructures in the field of molecular electronics is discussed with respect to electrical and optical switching properties of these films.