AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Monday Sessions
       Session NS2-MoM

Paper NS2-MoM10
Mechanical and Electromechanical Properties of Metallic Nanowires

Monday, October 31, 2005, 11:20 am, Room 210

Session: Nanowires
Presenter: B. Wu, Trinity College Dublin, Ireland
Authors: B. Wu, Trinity College Dublin, Ireland
A. Heidelberg, Trinity College Dublin, Ireland
J.J. Boland, Trinity College Dublin, Ireland
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Here, we present a general method to measure the full spectrum of nanowire (NW) mechanical properties: ranging from Youngs modulus E, yield strength, plastic deformation and failure. This method is based on NW bending under the lateral load from an atomic force microscope tip, and involves the manipulation of NWs after they have been mechanically pinned at the edge of a trench using a focused ion-beam. We find that for Au and Cu NWs the Youngs modulus (E) is essentially independent of diameter, while the yield strength is largest for the smallest diameter wires, with strengths up to 100 times that of bulk materials and substantially larger than that reported for bulk nanocrystalline metals (BNMs). In contrast to BNMs, NW plasticity is characterized by strain-hardening demonstrating that dislocation motion and pile up is still operative down to diameters of 40 nm. Possible origins for the different mechanical properties of NWs and BNMs are discussed. The application of this method has also been extended to electrical measurement of NW systems under mechanical strain. For metallic and conducting polymer NWs, the resistance was monitored when NWs were subjected to loads by AFM tip. The potential applications will be discussed.