科研之友
微信
新浪微博
Facebook
分享链接
摘要
Silicon (Si) nanostructures may play an important role in future nanoelectronics. Here, arrays of single vertically aligned Si nano-needles (SiNNs) are fabricated and found to exhibit a significant piezoresistance effect under large non-uniaxial strain. The experiments were performed by in situ manipulating of the SiNNs in a scanning electron microscope. The method enables us to determine the piezoresistance effect under the combined action of compressive and tensile strains, which is different from reported works on the piezoresistance effect of Si nanostructures under uniaxial/biaxial strains. This has given rise to an opportunity to further explore the physical origins responsible for the piezoresistance of Si. The relative change in resistivity under the non-uniaxial strain was calculated from the experimental I-V data. The results show that a greater piezoresistance effect can be achieved as compared with that of Si nanowires under uniaxial strain. We propose that the suppression of inter-valley scattering and the change of electron concentration caused by the energy band shift are the main reasons for the large piezoresistance effect.
