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Description
Atomically precise fabrication through the controlled reactivity and placement of chemical species was one of the goals defined within the earliest visions of nanotechnology. A first example of this, the controlled abstraction of a hydrogen atom from a passivated Si(100) surface through subtractive mechanosynthesis using a novel molecule (EAOGe-C2I) and inverted-mode scanning tunneling microscopy (IM-STM), has recently been reported [1]. The design criteria used in the development of this molecule produced a general structural framework for both the abstraction and donation of chemical groups to surfaces based on the reactivity and the competitive bonding of molecular fragments to a reactive surface [2].
This work demonstrates mechanosynthetic donation of C2 from an activated (de-iodinated) EAOGe-C2I molecule to a Si(100) build site . To promote controlled additive mechanosynthetic outcomes, the Si(100) surface was hydrogen-passivated, and bonding sites were selectively activated through dangling bond patterning. This site-specific activation of the build site facilitates the transfer of C2 into the target configuration – an inter-dimer-row bridging geometry of the Si(100)-2x1 surface reconstruction (“IR- C2”) – with high selectivity, marking the first controlled, repeatable example of additive mechanosynthesis and the first report of a carbon dimer in this configuration on silicon.
[1] E. Barrera et al., “Inverted-mode scanning tunneling microscopy for atomically precise fabrication,” arXiv:2512.24431 [cond-mat.mes-hall] (2025), https://doi.org/10.48550/arxiv.2512.24431 (submitted for peer review).
[2] T. Huff et al., “Molecular tools for non-planar surface chemistry,” arXiv:2508.16798 [cond-mat.mtrl-sci] (2025), https://doi.org/10.48550/arXiv.2508.16798 (submitted for peer review).
| Keyword-1 | Atomically precise fabrication |
|---|---|
| Keyword-2 | STM |