Crystallinity and surface effects on Young’s modulus of CuO nanowires

Abstract

The authors investigate the crystallinity and surface effects on Young’s modulus of cupric oxide (CuO) nanowires by performing three-point bend test using atomic force microscopy. Young’s modulus of the nanowires obtained ranges from 70to300GPa and is dependent on two factors. Firstly, it depends on whether the nanowire is mono- or polycrystalline, as indicated by the absence or presence of an amorphous surface layer. Second, the modulus increases with decreasing diameter for both types of nanowires. Combined with transmission electron microscopy and computational simulation studies, the nanostructure-mechanical property relationship of CuO nanowires is elucidated.

Contact-resonance atomic force microscopy for nanoscale elastic property measurements: Spectroscopy and imaging

“…5(a), that the indentation modulus is constant, around 45 GPa, for NWs thicker than 100 nm, monotonically increases from 45 to 85 GPa for NWs with thickness in the 100-30 nm range, and plateaus around 85 GPa for NWs thinner than 30 nm. This size-dependence of NWs elastic modulus differs from that previously reported for other types of NWs: over the investigated diameter range, a continuous increase in the elastic modulus was found with the reduction in diameter [30][31][32][33]15] but no plateau was observed in the range of very small diameters.…”

“…The size-dependence observed in the elastic response of NWs of reduced diameters [30][31][32][33][34]15] originates from the surface energy and surface stress effects in such nanostructures with large surface-to-volume ratio [35][36][37][38][39]. Symmetry destruction as well as relaxation of bonds due to uncoordinated atoms in the surface layers of NWs modify the surface energy, which, in turn, affects the mechanical properties of NWs.…”

Surface effect in the bending of nanowires

“…The effective elastic modulus of fixed-fixed nanowires is found to increase with a decreasing diameter of nanowires ( Cuenot et al, 2004;Chen et al, 2006;Jing et al, 2006;Tan et al, 2007;Chan et al, 2010;Celik et al, 2011 ). While for cantilever nanowires, the effective elastic modulus has an oppositely size-dependent behavior ( Nam et al, 2006;Gavan et al, 2009;Sadeghian et al, 2009Sadeghian et al, , 2010.…”

Morphology preservation and crystallinity improvement in the thermal conversion of the hydrothermal synthesized MgBO2(OH) nanowhiskers to Mg2B2O5 nanowhiskers

“…The novel properties of 1D nanostructures greatly depend on their morphology, aspect ratio and crystallinity [4][5][6][7][8][9]; thus it is of great significance to ascertain controllable synthesis of 1D nanostructures with uniform morphology, high aspect ratio and high crystallinity. 1D nanostructures could be obtained by a variety of synthetic methods [3], among which chemical vapor deposition (CVD) has been widely used particularly for its versatility [3,10] and high crystallinity [11], e.g.…”