Surface effects on the elastic modulus of Te nanowires

Nondestructive elastic property measurements have been performed on Te nanowires with diameters in the range 20-150 nm. By using contact resonance atomic force microscopy, the elastic indentation modulus perpendicular to the prismatic facets of the nanowires has been accurately quantified. In this diameter range, a pronounced size dependence of the modulus has been observed: an invariant value consistent with Te bulk properties for large wire diameters, followed by a nonlinear increase with decreasing diameter, and finally an almost doubling of the modulus for Te nanowires thinner than 30 nm. A model based on surface stiffening describes the observations. (C) 2008 American Institute of Physics.