Deformation-driven electrical transport in amorphous TiO2 nanotubes

A series of in situ transmission electron microscopy combined with scanning tunneling microscopy measurements were carried out to investigate the effect of mechanical deformation on the electrical transport properties of amorphous TiO2 nanotubes. Under no mechanical straining, it was found that the TiO2 nanotubes behave as electrical insulators. However, the nanotubes show semiconducting behavior under a highly deformed state. On the basis of a metal–semiconductor–metal model, it was suggested that in-shell defects, surface defect-driven conduction modes, are responsible for the appearance of the semiconducting behavior.