Optical doping: active control of metal-insulator transition in nanowire.

The reversible control of metal-insulator transition (MIT) in In/Si(111) nanowires is demonstrated by tuning the band filling of the one-dimensional surface state by optical doping. The control of MIT is carried out by regulating the Fermi level in the surface state around the half-filled position, depending on the carrier density introduced at the interface. We successfully achieved the reversible and active control of MIT via the charge doping by regulating the intensity of photoexcitation. This method is widely applicable to other low-dimensional systems and makes MIT more controllable and suitable for use in nanowires as an active element in future architectures of nanosized functional devices as well as nanoscale interdevice wiring.