Speaker
Description
Atomically precise manipulation of individual, covalently bonded atoms has been a difficult problem for both bottom-up and top-down approaches in nanotechnology. In this work, we employ our recently developed inverted-mode scanning tunneling microscopy (IM-STM) as a platform for atomically precise mechanosynthesis [1]. In our chosen application, individual Si atoms can be routinely abstracted from a Si(100) crystalline surface with sub-Ångström resolution by piezo-actuator controlled mechanical interaction with individual “molecular tools”, which serve both as local reagents for chemical modification of the Si probe and as in situ product-imaging molecules for IM-STM. We highlight the use of one such newly synthesized tripodal molecular tool: MAOC-C2I, for highly reproducible generation of individual and patterned Si vacancies and divacancies, as well as subsequent targeted reconstructions of the Si surface. The terminal ethynyl iodide (-C2I) functional group of the covalently surface-bound MAOC-C2I, once “activated” in situ with applied bias pulses, presents a –C2* radical moiety anchored by a C bridgehead atom to bond with and mechanically abstract the target Si atom from a Si(100)-2x1 dimer pair. Our results demonstrate new routes to patterning the Si(100) surface as a potential complementary technique to hydrogen depassivation lithography, highlighting additional capabilities towards atomically precise fabrication. These advances show promise for further developments in mechanosynthesis-enabled nanotechnologies with the highly flexible chemical platform afforded by our molecular tool design [2].
- 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).
- 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 | scanning tunneling microscopy |
|---|---|
| Keyword-2 | silicon abstraction |
| Keyword-3 | atomically precise fabrication |