Strain-Induced Interfacial Bond Evolution and Facet-dependent Strain Response of Electronic Properties in Oxidized Silicon Nanowires

Abstract

Silicon nanowires (Si NWs) have emerged as promising candidates for next-generation nanoelectronic devices due to their tunable electronic properties, and compatibility with aggressive scaling requirements. The integration of strain further enhances their performance by modulating carrier mobility, band structure, and transport behavior without altering material chemistry. Within the NW, the silicon-silicon dioxide (Si-SiO$_{2}$) interface serves as a critical region where strain redistribution and suboxide bonding collectively influence the mechanical and electronic response. Here, we combine reactive force field molecular dynamics and first-principles calculations to investigate how oxidation-induced interfacial structure and crystallographic facet orientation govern strain-dependent bond evolution and facet-dependent strain response of electronic properties in oxidized Si NWs. Simulated dry thermal oxidation generates chemically realistic Si-SiO$_{2}$ interfaces, enabling direct characterization of bond order redistribution and stress gradient development across the interface under tensile strain. Interfacial Si-Si bonds exhibit elongation and reduced bond order associated with partial oxidation states, leading to localized stress concentration and preferential bond rupture. Complementary density functional theory calculations on facet-specific models reveal that orientation-dependent interfacial bonding modulates facet-dependent strain response of electronic properties. Together, these results establish a direct coupling between interfacial suboxide chemistry, mechanical deformation, and electronic structure, providing atomistic insight into strain-modulated behavior at oxidized silicon interfaces in faceted NWs.