Experimental evaluation of the mechanical properties of iron oxide nanowires for chemical sensor applications

The mechanical properties and structural robustness of iron oxide (Fe 2 O 3 ) nanowires (NWs) were experimentally investigated to enable their reliable integration into nanodevices. In this study, in situ tensile and bending tests were conducted within a scanning electron microscopy to evaluate the mechanical properties of single Fe 2 O 3 NWs formed via stress-induced migration during thermal treatment of an iron plate substrate. The tensile strength of individual single NWs increased from 0.11 to 1.72 GPa while the fracture diameter decreased from 840 to 130 nm. The bending strength of single NWs on the substrate was approximately 1.31 GPa at a fracture diameter of 251–381 nm. These mechanical strengths are primarily attributed to the radial oxygen heterogeneity between the core and outer regions of the NWs, likely induced by stress migration during NW formation. A chemical sensor based on the NWs on the substrate demonstrated good sensing properties and high durability for ethanol solutions. Overall, the mechanical robustness of Fe 2 O 3 NWs, as demonstrated by experimental evaluations of mechanical strength and solution-sensing properties, provides a new strategy for the rational design and practical implementation of high-performance, reliable future nanodevices.