In Situ Nano-thermomechanical Experiment Reveals Brittle to Ductile Transition in Silicon Nanowires
| Autor: | Ting Zhu, Qunfeng Liu, Yong Zhu, Wei Lu, Lin Chen, Yin Zhang, Guangming Cheng, Tzu-Hsuan Chang |
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| Rok vydání: | 2019 |
| Předmět: |
Nanostructure
Materials science Silicon business.industry Mechanical Engineering Nanowire chemistry.chemical_element Bioengineering 02 engineering and technology General Chemistry Plasticity 021001 nanoscience & nanotechnology Condensed Matter Physics Brittleness chemistry Nano Microelectronics General Materials Science Composite material Dislocation 0210 nano-technology business |
| Zdroj: | Nano Letters. 19:5327-5334 |
| ISSN: | 1530-6992 1530-6984 |
| Popis: | Silicon (Si) nanostructures are widely used in microelectronics and nanotechnology. Brittle to ductile transition in nanoscale Si is of great scientific and technological interest but this phenomenon and its underlying mechanism remain elusive. By conducting in situ temperature-controlled nanomechanical testing inside a transmission electron microscope (TEM), here we show that the crystalline Si nanowires under tension are brittle at room temperature but exhibit ductile behavior with dislocation-mediated plasticity at elevated temperatures. We find that reducing the nanowire diameter promotes the dislocation-mediated responses, as shown by 78 Si nanowires tested between room temperature and 600 K. In situ high-resolution TEM imaging and atomistic reaction pathway modeling reveal that the unconventional 1/2⟨110⟩{001} dislocations become highly active with increasing temperature and thus play a critical role in the formation of deformation bands, leading to transition from brittle fracture to dislocation-mediated failure in Si nanowires at elevated temperatures. This study provides quantitative characterization and mechanistic insight for the brittle to ductile transition in Si nanostructures. |
| Databáze: | OpenAIRE |
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