Atomic Mechanisms Governing the Elastic Limit and the Incipient Plasticity of Bending Si Nanowires

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• 作者：Kun Zheng ; Xiaodong Han ; Lihua Wang ; Yuefei Zhang ; Yonghai Yue ; Yan Qin ; Xiaona Zhang ; Ze Zhang
• 刊名：Nano Letters
• 出版年：2009
• 出版时间：June 10, 2009
• 年：2009
• 卷：9
• 期：6
• 页码：2471-2476
• 全文大小：457K
• 年卷期：v.9,no.6(June 10, 2009)
• ISSN：1530-6992

文摘

Individual single-crystalline Si nanowires (NWs) were bent by forming loops or arcs with different radius. Positional-resolved atomic level strain distribution (PRALSD) along both of the radial and axial directions were calculated and mapped directly from the atomic-resolution strained high-resolution electron microscopy (HREM) images of the bent Si NWs. For the first time, the neutral-strain axis shifted from the compressive zone to the tensile region was directly demonstrated from the PRALSD along the radial direction. Bending-induced ripple-buckling of the bent Si NW was observed and a significant strain variation along the bending axial direction in the compressive region was revealed. The tensile surface atomic steps and the compressive buckling are the physical origin of the asymmetric tensile-compressive properties of postelastic instabilities and the incipient plasticity. Both of the tensile surface atomic-steps and the compressive buckling initiated versatile ductile plastic dislocation events.