Regensburg 2025 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

O: Fachverband Oberflächenphysik

O 98: Metal and Semiconductor Substrates: Adsorption and Reactions of Small Molecules

O 98.3: Talk

Friday, March 21, 2025, 11:00–11:15, H8

Electron-Induced Dehydrogenation of Acetylene and Ethylene on Si(100) — Rafik Addou, Damian Allis, Ryan Groome, Si Yue Guo, Aru Hill, Hadiya Ma, Cameron Mackie, •Oliver MacLean, Marc Savoie, Marco Taucer, Alexander Therien, Finley van Barr, and Ryan Yamachika — CBN Nanotechnologies Inc.

Low-Temperature Scanning Tunneling Microscopy (STM) is a powerful tool for manipulating individual atoms and molecules on surfaces. The Si(100) surface is a technologically relevant substrate; however, its high reactivity and structural complexity has led to limited examples of molecular manipulation. Here, we demonstrate the electron-induced dehydrogenation of two simple hydrocarbons on Si(100) at 4 K. Excitation by tunneling electrons at or above +3.2 V led to rotation, migration, or desorption of acetylene, consistent with previous observations on ethylene. At similar biases, dehydrogenation to C2 was also observed, which bound in on-dimer, inter-dimer, and inter-row configurations, as supported by STM simulations. At +4.2 V and above, excitation induced rotation of C2 between configurations, but conversion back to the starting adsorbates was never observed. Tunneling-electron excitation of ethylene yielded the same C2 products. Dehydrogenation of acetylene by field emission was also observed, with an effect ranging from a single to thousands of molecules, depending on the parameters chosen. This exploration of electron-induced dehydrogenation and rotation points to new possibilities in molecular manipulation on semiconductors.

Keywords: scanning tunneling microscopy (STM); ultra-high vacuum (UHV); Si(100); electron-induced reaction; organic molecules