Amine-directed adsorption of 2-thiophenemethylamine on Si(100)-(2 × 1)

The controlled functionalization of silicon surfaces with conjugated organic molecules is an im portant strategy for the development of hybrid semiconductor interfaces with tailored chemical and electronic properties. In this work, the adsorption of 2-thiophenemethylamine (AMTP) on the Si(100)-(2×1) reconstructed surface was investigated through a combined experimental and theoretical approach involving scanning tunneling microscopy (STM), low-energy electron diffrac simulatedSTM imaging. LEED tion (LEED), density functional theory (DFT) calculations, and measurements confirmed preservation of the Si(100)-2×1 reconstruction after molecular deposition, while STM revealed recurrent localized and paired adsorption features distributed across the surface.DFT calculations indicate that the most stable adsorption pathway corresponds to dissociative Si–N anchoring accompanied by proton transfer to the same silicon dimer.In contrast to unsubstituted aminothiophene systems, the presence of the methylene spacer redirects adsorp thiophene and tion away from ring-mediated cycloaddition processes, favoring preservation of the thiophene aro- maticity and suppressing molecular fragmentation under room-temperature conditions. Simulated coverage reproduce the elongated and multi-lobed STM images obtained for increasing molecular features observed experimentally, showing satisfactory agreement with the measured surface morphologies. The results highlight the role of molecular architecture in directing adsorption selectivity and interface formation on reactive silicon surfaces, providing insight into the bottom-up design of silicon–organic hybrid interfaces