کنفرانس مهندسی برق ایران

صفحه اصلی / سی و چهارمین کنفرانس بین المللی مهندسی برق

Evolution of Silicon Nanosheets and Fluorinated Silicene on Si(111) Substrate via Plasma-Enhanced Hybrid Physical–Chemical Vapor Deposition

نویسندگان :

Ehsan Karimi¹ Mohammad Hosseini² Shamsoddin Mohajerzadeh³

1- دانشگاه تهران 2- پژوهشگاه دانش‌های بنیادی 3- دانشگاه تهران

کلمات کلیدی :

Silicene،Two-dimensional materials،Fluorinated silicene nanosheets،Silicon nanosheets،Silicon nanosheets

چکیده :

Two-dimensional nanomaterials, owing to their unique physical and chemical properties, have emerged as promising building blocks for next-generation electronic devices. Following the discovery of graphene, considerable effort has focused on silicon-based analogues that are more compatible with established semiconductor technology. However, the intrinsic preference of silicon for sp3 hybridization and its strong tendency toward oxidation have hindered the synthesis and stabilization of its two-dimensional counterpart, silicene. In this work, we present a plasma-assisted growth route for producing silicene-based nanosheets directly on Si (111) substrates in a custom plasma-enhanced hybrid physical-chemical vapor deposition system. Sequential helium, hydrogen, and neon plasmas are used to activate the surface, weaken interlayer Si-Si bonds, and promote the formation of quasi-free two-dimensional silicon layers, which are subsequently detached and stabilized through a photochemical fluorination process based on hexafluorosilicic acid. The resulting fluorinated silicene nanosheets, with lateral dimensions exceeding several micrometers and near-nanometer thicknesses, are characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, grazing-incidence X-ray diffraction, and X-ray photoelectron spectroscopy. The combined results confirm the formation of well-ordered, chemically stable, fluorinated silicene nanosheets. Finally, these nanosheets are integrated as the active channel in back-gated field-effect transistors, which exhibit symmetric ambipolar transport and an ON/OFF current ratio above 17 for a 10-micrometer channel length. These findings demonstrate a viable path toward integrating fluorinated silicene into future nanoelectronic and optoelectronic technologies.