Thin Films of Molecular Metals: TTF-TCNQ

We present recent results on the characterization of highly-ordered polycrystalline thin films of the charge transfer salt TTF-TCNQ (TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane) prepared by thermal sublimation in high vacuum under different conditions. The increase in orientation and microcrystal size as a function of substrate and annealing temperatures is addressed. A consequence of such an increase is the reduction of the conductivity activation energy, which eventually leads to the observation of the Peierls transition by resistivity measurements. X-ray Absorption Near Edge Spectroscopy (XANES) studies performed with synchrotron radiation reveal directly the influence of charge transfer on unoccupied states near the Fermi level.