Two-Terminal Nanoelectromechanical Devices Based on Germanium Nanowires

A two-terminal bistable device, having both ON and OFF regimes, has been demonstrated with Ge nanowires using an in situ TEM−STM technique. The function of the device is based on delicately balancing electrostatic, elastic, and adhesion forces between the nanowires and the contacts, which can be controlled by the applied voltage. The operation and failure conditions of the bistable device were investigated, i.e. the influence of nanowire diameter, the surface oxide layer on the nanowires and the current density. During ON/OFF cycles the Ge nanowires were observed to be more stable than carbon nanotubes, working at similar conditions, due to the higher mechanical stability of the nanowires. The higher resistivity of Ge nanowires, compared to carbon nanotubes, provides potential application of these 1D nanostructures in high-voltage devices.