Using a scanning tunneling microscope, we can study the structure of surfaces at the atomic level and the binding of adsorbates on them.
The surfaces of Cu(111), the insulating layer of CuN on Cu(111), Ag(111) and Au(111) were studied. On clean surfaces, we observed atomic steps and standing waves on them. Based on the measured steps heights, we determined the calibration of the microscope at different temperatures. An interesting surface reconstruction was observed for the CuN and Au(111) surfaces. Au(111) is characterized by a herringbone structure resulting from the transition between the face-centered cubic structure to a hexagonal close-packed one, and at the CuN surface we observed a reconstruction of the Cu(111) surface into pseudo-Cu(100) which occurs due to the binding of nitrogen atoms.
In the second part experiments of the self-assembly of 2-mercaptobenzimidazole (2-MBI) molecules on the above-mentioned surfaces are presented. We know that these molecules are good organic corrosion inhibitors and bind well to copper, so we were interested in how these molecules will behave on copper-like surfaces and what their behaviour will be like when they are decoupled from the substrate. We found that 2-MBI only weakly binds to the CuN layer and Ag(111). We observed that molecules are mobile on these surfaces and that they prefer to form bonds between themselves rather than with the surface atoms. In contrast to Cu(111), no ordered self-assembly structures could be observed in our experiments.
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