Elastic Stretch Limit Exceeding 10% for Silicon Wires with Submicron to Micron Diameters

It is significant to modulate the bandgap of crystalline silicon (c‐Si) by applying large strains on it through controlled stretch. However, investigations on the stretchability of c‐Si are still insufficient, especially for samples with feature sizes in the submicron to micron scale. In this work, the large stretchability of silicon wires with submicron to micron diameters (SiMWs) is reported for the first time by using vapor–liquid–solid grown ultralong SiMWs. The diameters of the SiMW specimens range from 400 nm to 1.8 μm. The loading speed for stretching SiMWs is 100 nm s⁻¹. It is found that the SiMWs with micron diameter have a stretch limit over 10%, while the stretch limit for samples with submicron diameter can reach 12%. The results fill the gaps in the knowledge of micron‐scale silicon materials’ stretchability. The average Young's modulus of SiMWs is measured as 115 GPa. Cyclic loading tests indicate that the tensile deformation of SiMWs is elastic and reversible with no plastic deformation observed. In this work, it is shown that large stretch of SiMWs can be achieved without the need of harsh experimental conditions, which will greatly facilitate the study of large strain engineering on c‐Si to modulate their properties and broaden their applications.