Experimental Investigation of Fundamental Mechanical Behavior of Silicon Nanowires

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This research is about the correlation between the size effects of silicon nanowires on elasticity, fracture, and their brittle to ductile transition.. In-situ scanning/transmission electron microscopy resonance and tensile testing on the same single NWs will be conducted to measure the elastic behavior. A statistical, Weibull-type, probability model will be employed to analyze the fracture data and identify fracture origins with the assistance of real-time and post-mortem microscopy analyses. In-situ thermomechanical testing done in-situ, in a Transmission Electron Microscope using a novel microfabricated testing stage will be used to probe the brittle to ductile transition.If successful, the proposed research has potential to improve flexible and stretchable electronics, improve energy conversion and storage. It is anticipated that the experimental results will be used in a collaborative way to develop atomistic simulations that will pin down the mundamental mechnisms of nanoscale elasticity, fracture and brittle to ductile transition. In addition, the novel experimental tools and methods developed in this project (e.g., the microfabricated thermomechanical testing stage) can be used to understand the properties of a broad range of nanostructures. From a teaching perspective, this work will be: 1) integrated into undergraduate and graduate courses that PI offers at NCSU (including a NSF supported undergraduate nanotechnology laboratory course), and web-based dissemination of the new course module; 2) used for training of graduate and undergraduate students for multidisciplinary research with involvement of women and underrepresented minorities; 3) used for collaboration with the Engineering Place program at North Carolina State University to develop an interactive demonstration module and present it to K-12 students.