Initial stages of metal/organic semiconductor interface formation

We have used photoelectron spectroscopies to study the metal/organic semico nductor interfaces formed by depositing three different metal-quinolate der ivatives on Ag, with the goal of better understanding the initial stages of interface formation. We find very consistent results at all three interfac es, which exhibit strong energy level shifts within the first molecular lay er, followed by a nearly "flat-band" condition. These results were analyzed in the context of the interface dipole and "band-bending" models. We concl ude that the interface dipole model, extended to account for the difference s in polarization screening in the first molecular layer, most accurately d escribes our findings. In this article we present the most thorough descrip tion of the early stages of metal/molecular organic semiconductor interface s to date. (C) 2000 American Institute of Physics. [S0021-8979(00)02814-0].