Abstract
We have studied the interfacial structures of TTC on uniform Ag thin films grown on Ge(111) by angle-resolved photoemission spectroscopy (ARPES) through the quantum- well states (QWSs) of the silver thin films. From the experimental results, we found that both the quantum-well-state energy positions and the vacuum-level shift depend on the coverage of TTC layer. The Ag QWSs shift toward the Fermi level and the vacuum level decreases with the increasing coverage of TTC films. We used the mirror-force model coupled with Bohr-Sommerfeld quantization rule to quantitatively simulate our measured energy shift of QWSs versus Ag thickness upon adsorption of 1 ML TTC films. The phase change at the film/vacuum interface thus derived is -0.62±0.08 and the resulting dielectric constants for 1 ML TTC film by applying modified image potential model is 1.30~1.51.