In-situ mechanical characterization of wurtzite InAs nanowires

High aspect ratio vertical InAs nanowires were mechanically characterized in a scanning electron microscope equipped with two micromanipulators. One, equipped with a calibrated atomic force microscope probe, was used for in-situ static bending of single nanowires along the 〈11–20〉 crystallographic direction. The other one was equipped with a tungsten tip for dynamic resonance excitation of the same nanowires. This setup enabled a direct comparison between the two techniques. The crystal structure was analyzed using transmission electron microscopy, and for InAs nanowires with a hexagonal wutzite crystal structure, the bending modulus value was found to BM=43.5 GPa. This value is significantly lower than previously reported for both cubic zinc blende InAs bulk crystals and InAs nanowires. Besides, due to their high resonance quality factor (Q>1200), the wurtzite InAs nanowires are shown to be a promising candidate for sub-femtogram mass detectors.

highlights► High aspect ratio vertical InAs nanowires were mechanically characterized in a SEM. ► The nanowires are wurtzite type single crystals of high quality. ► We applied a static and a dynamic method on the same individual nanowires. ► The two different techniques cross-confirmed each other. ► The obtained Young's modulus is lower than the bulk value.