title: Interaction of a conjugated polyaromatic molecule with a single dangling bond quantum dot on a hydrogenated semiconductor.
abstract: Controlling the strength of the coupling between organic molecules and single atoms provides a powerful tool for tuning electronic properties of single-molecule devices. Here, using scanning tunneling microscopy and spectroscopy (STM/STS) supported by theoretical modeling, we study the interaction of a planar organic molecule (trinaphthylene) with a hydrogen-passivated Ge(001):H substrate and a single dangling bond quantum dot on that surface. The electronic structure of the molecule adsorbed on the hydrogen-passivated surface is similar to the gas phase structure and the measurements show that HOMO and LUMO states contribute to the STM filled and empty state images, respectively. Furthermore, we show that the electronic properties are not significantly affected when the molecule is attached to the single dangling bond, which is in contrast with the strong interaction of the molecule with a dangling bond dimer. Our results show that the dangling bond quantum dots could stabilize organic molecules on a hydrogenated semiconductor without affecting their originally designed gas phase electronic properties. Together with the ability to laterally manipulate the molecules on the surface, this will be advantageous in the construction of single-molecule devices, where the coupling and positioning of the molecules on the substrate could be tuned by a proper design of the surface quantum dot arrays, comprising both single and dimerized dangling bonds.
authors.affiliation: Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, PL 30-348, Krakow, Poland. szymon.godlewski@uj.edu.pl.
authors.forename: Szymon
authors.initials: S
authors.lastname: Godlewski
authors.forename: Marek
authors.initials: M
authors.lastname: Kolmer
authors.forename: Mads
authors.initials: M
authors.lastname: Engelund
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Kawai
authors.forename: Rafal
authors.initials: R
authors.lastname: Zuzak
authors.forename: Aran
authors.initials: A
authors.lastname: Garcia-Lekue
authors.forename: Mark
authors.initials: M
authors.lastname: Saeys
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Echavarren
authors.forename: Christian
authors.initials: C
authors.lastname: Joachim
authors.forename: Daniel
authors.initials: D
authors.lastname: Sanchez-Portal
authors.forename: Marek
authors.initials: M
authors.lastname: Szymonski