Molecular adsorption: From single molecules to covalent structures

Germar Hoffmann^1,2*

¹Department of Physics, NTHU, Hsinchu, Taiwan
²Center for Quantum Technology, NTHU, Hsinchu, Taiwan

* Presenter:Germar Hoffmann, email:germar.hoffmann@googlemail.com

Devices fabricated atom by atom represent the ultimate goal of chip design. Although structuring technologies continue to push into the nanometer regime, design and control at the true atomic scale remain elusive. In contrast, chemistry—with its highly developed process control—offers a vast range of functional organic systems, yet their structural upscaling and integration are limited by synthetic constraints.

Over the past decade, a promising alternative known as On-Surface Synthesis (OSS) has emerged at the intersection of materials science, chemistry, and physics. Inspired by classical synthetic chemistry, OSS enables the covalent coupling of simple organic precursors directly on well-defined substrates. This approach provides unprecedented access to intramolecular physical phenomena within a fully controlled molecular environment. Yet, systematic process control—beyond the conventional tuning of substrates, precursors, and temperatures—has only recently begun to develop.

Despite remarkable advances, integrating such molecular architectures into practical device geometries still demands substantial progress in process control, particularly in achieving selective cross-coupling and effective electronic insulation from the substrate. In this talk, I will introduce the field of On-Surface Synthesis and discuss our recent advances and contributions from single molecule adsorption to covalent systems in STM/STS studies toward bridging this approach with atomic-scale device concepts.

Keywords: Molecules, Adsoprtion, Covalent Coupling, Scanning Tunneling Microscopy, Process Conntrol