Nanowire mechanical switch with a built-in diode.

Figure 1. Schematic diagramof a cross-point switch (a), which consists of a Cartesian matrix of orthogonal wires with an air gap at each intersection. The switch at each intersection can be turned on and off by The main driving engine of the IT revolution has been geometry miniaturization of transistors. This has been accomplished with a striking development in microfabrication technology, referred to as ‘‘Moore’s law;’’: the number of transistors on an integrated circuit (IC) doubles every 2 years, and industrial guidelines enable multiple devices to be integrated within a given chip area. However, as the gate insulator thickness shrinks below 2 nm and the distance between the source and drain is reduced below 50 nm, gate leakage and subthreshold leakage current flow even though the transistor is supposed to be off. Standby power when devices are supposed to be in the off state therefore occupies a significant portion of total power consumption. In addition, this situation has pushed the metal–oxide–semiconductor (MOS) transistor to the end-point of the international technology roadmap for semiconductors (ITRS). Thus, the development of a new device that consumes low power is an important undertaking. In the mechanical switch, since two electrodes are physically separated in the off state, the power consumption in the off state is ideally zero. In particular, as the accumulated heritage from semiconductor fabrication technology enables device sizes from the microto nanoscale regime, realization of a mechanical switch on the nanoscale will become more feasible. In the previously proposed approach, two terminal mechanical switches are arranged in a cross-point structure (Figure 1a). A bistable property of the cross-point structure also leads to a basis of binary digits, where information is detected by measuring the contact resistance at the cross-point: high contact resistance at the switch-off state (Figure 1b) or low contact resistance at the switch-on state (Figure 1c). These cross-point devices have been explored by the bottom-up assembly of various materials, such as carbon nanotubes, silicon–