Growth process and compressed phase of DMe-DCNQI on Ag(110) in the monolayer regime observed by LEED, XPS, and STM

Publisher Website
Google Scholar
Abstract
2,5-dimethyl-dicyanoquinonediimine films were grown on Ag(110) by organic molecular-beam deposition in an ultrahigh vacuum. During the preparation, the films were characterized in situ by low-energy electron diffraction. At distinguished stages of the preparation, x-ray photoelectron spectroscopy (XPS), and scanning tunneling microscopy (STM) were carried out. Two commensurate structures were found in two domain orientations. The first commensurate structure arose from a disordered arrangement (diffuse diffraction). At a certain substrate coverage, a second structure representing a compressed phase emerged from the first. In addition to the different unit cell sizes the structures differed in molecular orientation as verified by STM investigations. In addition to the major structural transitions, two minor modifications were observed. The XPS data indicate that in the monolayer regime an electron charge transfer occurs in all investigated structures from the metallic substrate to the molecule.