Impact of native oxide on the vibrational response of silicon nanowires

Abstract

The vibrational performance of silicon nanowires is strongly influenced by surface chemistry and crystallographic orientation, particularly at sub-10 nm dimensions. In this study, molecular dynamics simulations are employed to investigate the fundamental out-of-plane vibrational response of double-clamped silicon nanowires with and without an amorphous native oxide layer. Resonance frequencies and quality factors are systematically analyzed across multiple widths, length-to-width aspect ratios, and crystallographic orientations (<100>,<110>,<111>,<112>). The results reveal that the presence of a native oxide layer induces a pronounced reduction in resonance frequency (up to 50%) and dramatically lowers the quality factor by several orders of magnitude, indicating significantly enhanced damping due to surface-induced disorder and energy dissipation. While pristine silicon nanowires exhibit strong orientation-dependent variations in resonance behavior and minimal damping, silicon nanowires with native oxide surface are dominated by surface effects, with crystallographic orientation playing a secondary role. These findings highlight the critical importance of incorporating realistic surface conditions in modeling nanoscale systems and provide key insights for the design and optimization of silicon nanowire-based resonators and MEMS/NEMS devices.