Apr 20, 2009
'Poking' nanowires provokes elastic response
Understanding the elastic behaviour of functional metal oxide nanowires (NWs) is crucial when it comes to designing reliable, long lasting, bendable devices and assessing their resistance to mechanical failure. Here, atomic force microscopy is a useful tool, as researchers explain in Nanotechnology.
The scientists grew oriented tin oxide NWs on rutile substrates and probed the material with an atomic force microscope (AFM) to determine the sample's elastic properties. To keep track of the geometrical arrangement of the NW–tip interaction, the position of the AFM probe was monitored by a coupled scanning electron microscope.
The elastic properties of the single crystalline SnO2 nanowires were investigated in a two point-geometry as shown above. The corresponding Young's modulus was estimated by bending individual NWs and measuring the force exerted on the AFM tip during force-displacement measurements. For the NWs investigated (radial dimensions below 45 nm and length up to 1.2 µm), the researchers found an average value of 100±20 GPa, which is consistent with the indentation modulus of nanobelts. In addition, the group discussed the effects of the nanowire-cantilever configuration on the measured elastic modulus.
About the author
Dr Sven Barth is currently a postdoctoral fellow at the University College Cork, Ireland, working on the synthesis and characterization of semiconductor heterostructures and their controlled doping. Prof. Federico Rosei holds the Canada Research Chair in organic and inorganic nanostructured materials at INRS, Université du Québec. His expertise and research interests include the growth and characterization of semiconductor nanostructures, functional thin films, 2D supramolecular assemblies and 2D polymers, nano-bio interfaces and materials for energy applications (www.nanofemtolab.qc.ca). The work presented here was carried out in the framework of the Bavaria-Quebec research initiative.