Computational Insights into the Energetics of Single C-C Aliphatic Moieties Adsorbed on the Hydrogenated Silicon (111) Surface.

Silicon's versatility as a semiconductor renders it indispensable across various domains, including electronics, sensors, and photovoltaics. Modifying hydrogen-terminated silicon surfaces with moiety adsorption offers a method to tailor the material's properties for specific applications. In this study, we employ ab initio density functional theory calculations to explore the energetics of single alkyl, 1-alkenyl, and 1-alkynyl moieties chemisorbed on the hydrogen-terminated silicon (111) surface. We analyze the interfacial dipole induced by Si-C bond formation that determines the Schottky barrier and examine the alignment of the frontier orbital energy levels with the silicon band structure to investigate charge transfer based on the tunneling mechanism. Our findings provide valuable insights into how aliphatic moiety functionalization affects interfacial electronic properties, offering clues for optimizing silicon-based devices.