A strong saddle-shaped surface-to-volume ratio effect on the Young's modulus of silicon nanotubes

Abstract

Single crystalline silicon nanotubes along the [001] direction with different outer diameters and wall thicknesses have been successfully prepared via a high-fidelity nanofabrication process by combining electron-beam lithography and reactive-ion etching methods. A higher specific surface-to-volume ratio compared with other solid one-dimensional nanomaterials has been achieved. In situ compression results revealed a strong saddle-shaped surface-to-volume ratio effect on the Young's modulus, and the Young's modulus increases to a peak value at a surface-to-volume ratio of ∼0.04 nm−1 and then decreases at a higher surface-to-volume ratio. A single core with a double shell model is proposed to interpret this unique saddle-shaped surface-to-volume ratio effect, which may play a guiding role in designing the nanoscale objects for device applications.