Journal ArticleDOI
The electromechanical response of silicon nanowires to buckling mode transitions
Chee Chung Wong,Julien Reboud,Pavel Neuzil,Jeffrey B.W. Soon,Ajay Agarwal,Naranayan Balasubramanian,Kin Liao +6 more
TLDR
The highly flexible silicon nanowires embedded in SiO(2) microbridges exhibited unusually large fracture strength, sustaining tensile strains up to 5.6%; this will prove valuable in demanding flexible sensors.Abstract:
Here we show how the electromechanical properties of silicon nanowires (NWs) are modified when they are subjected to extreme mechanical deformations (buckling and buckling mode transitions), such as those appearing in flexible devices. Flexible devices are prone to frequent dynamic stress variations, especially buckling, while the small size of NWs could give them an advantage as ultra-sensitive electromechanical stress sensors embedded in such devices. We evaluated the NWs post-buckling behavior and the effects of buckling mode transition on their piezoresistive gauge factor (GF). Polycrystalline silicon NWs were embedded in SiO2 microbridges to facilitate concurrent monitoring of their electrical resistance without problematic interference, while an external stylus performed controlled deformations of the microbridges. At points of instability, the abrupt change in the buckling configuration of the microbridge corresponded to a sharp resistance change in the embedded NWs, without altering the NWs' GF. These results also highlight the importance of strategically positioning the NW in the devices, since electrical monitoring of buckling mode transitions is feasible when the deformations impact a region where the NW is placed. The highly flexible NWs also exhibited unusually large fracture strength, sustaining tensile strains up to 5.6%; this will prove valuable in demanding flexible sensors.read more
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Journal ArticleDOI
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Mechanical elasticity of single and double clamped silicon nanobeams fabricated by the vapor-liquid-solid method
A. San Paulo,Jeffrey Bokor,Roger T. Howe,Rongrui He,Peidong Yang,Di Gao,Carlo Carraro,Roya Maboudian +7 more
TL;DR: In this paper, the authors demonstrate the potential of the nanowire-in-trench fabrication approach for the integration of VLS grown nanostructures into functional nanomechanical devices.
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Lateral buckling mechanics in silicon nanowires on elastomeric substrates
Seung Yoon Ryu,Jianliang Xiao,Won Il Park,Kwang Soo Son,Yonggang Huang,Ungyu Paik,John A. Rogers +6 more
TL;DR: Experimental and theoretical studies of the buckling mechanics in silicon nanowires (SiNWs) on elastomeric substrates suggest that the energy associated with this in-plane buckling is slightly lower than the out-of-plane case for the geometries and mechanical properties that characterize the SiNWs.
Journal ArticleDOI
Nonlinear piezoresistance effects in silicon
TL;DR: In this paper, the second-order piezoresistance coefficients in various configurations of uniaxial stress, current, and crystallographic orientation were calculated by the sixth rank tensor transformation.