Godlewski Szymon, Kolmer Marek, Engelund Mads, Kawai Hiroyo, Zuzak Rafal, Garcia-Lekue Aran, Saeys Mark, Echavarren Antonio M, Joachim Christian, Sanchez-Portal Daniel, Szymonski Marek
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.
Phys Chem Chem Phys. 2016 Feb 7;18(5):3854-61. doi: 10.1039/c5cp07307c. Epub 2016 Jan 14.
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.
控制有机分子与单原子之间的耦合强度为调节单分子器件的电子特性提供了一种强大的工具。在此，我们利用理论建模支持的扫描隧道显微镜和光谱学（STM/STS），研究了平面有机分子（三联萘）与氢钝化的Ge(001):H衬底以及该表面上的单个悬空键量子点之间的相互作用。吸附在氢钝化表面的分子的电子结构与气相结构相似，测量结果表明，最高占据分子轨道（HOMO）和最低未占分子轨道（LUMO）状态分别对STM的填充态和空态图像有贡献。此外，我们表明，当分子连接到单个悬空键时，其电子特性不会受到显著影响，这与分子与悬空键二聚体的强相互作用形成对比。我们的结果表明，悬空键量子点可以在氢化半导体上稳定有机分子，而不会影响其原本设计的气相电子特性。结合在表面上横向操纵分子的能力，这将有利于单分子器件的构建，在单分子器件中，可以通过适当设计包含单个和二聚化悬空键的表面量子点阵列来调节分子在衬底上的耦合和定位。
