Ab-initio simulation of the tensile strength of silicon nanofilms

Abstract

Abstract Investigations of the relation between atomic configuration and strength at atomic and electronic level are important not only for understanding the fundamental deformation behavior of materials but also for application of materials to nanostructured devices. In this study, simulation of tension of silicon nanofilms under tensile stress was carried out using ab initio density functional theory calculation to investigate the effect of surface structure on tensile strength. Nanofilms with various surface orientations were examined. The theoretical tensile strength of Si nanofilms with a thickness of around 1.0 nm having (100) surfaces, which are flat with dimer-row structure, was only slightly lower than that of bulk Si. In contrast, surfaces with rather high Miller indices can significantly reduce critical strain owing to surface steps, indicating that such atomic-level structure affects the strength quite strongly.