Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 45: Organic-Inorganic Hybrid Systems and Organic Films

O 45.1: Poster

Dienstag, 21. März 2017, 18:30–20:30, P1A

Preparation of well-defined metal films on top of self-assembled monolayers — •Michael Zharnikov — Applied Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany

Self-assembled monolayers (SAMs) can be potentially used as ultrathin insulating dielectric layers or intermediate films in future electronic and spintronic devices. Whereas the bottom electrode in such devices is provided by the metal substrate, the top electrode should be prepared in controlled fashion at the SAM-ambient interface. Regretfully, this is a non-trivial task, since the metal atoms deposited onto the SAM-ambient interface do not stay there, but penetrate into the monolayer and diffuse to the metal substrate. Here I discuss three new approaches to suppress the above penetration and diffusion, taken nickel, as a test adsorbate. The first approach relies on irradiation-induced cross-linking of a thiol-substituted aromatic SAM. Whereas 2D-polymerization of such a SAM prevents penetration of the metal atoms into the monolayer, the thiol groups at the SAM-ambient interface serve as nucleation centers for the growing "top" metal film. The second approach, relying on SAMs of perfluoroterphenyl-substituted alkanethiols, utilizes a chemical reaction between the SAM constituents and adsorbate atoms. Finally, the penetration of deposited metal atoms into a SAM can be nearly completely inhibited by preliminary formation of palladium-chloride seeding layer at the SAM-ambient interface. The Pd atoms in the seeding layer serve as nucleation centers for the growing metal film while the Cl atoms perform as surfactants.