Piezoelectric gated diode of a single ZnO nanowire

The use of an n-type ZnO Nanowire (NW) to produce a p-n junction that served as a diode, was analyzed. In situ I-V measurements and the manipulation of ZnO NWs were carried out in an multiprobe nanoelectronics measurement (MPNEM) system. The two-terminal method was applied for electrical transport measurements at high vacuum to minimize influences from the environment. A tungsten nanotip was used for measuring the electrical transport of a nanowire that was precoated with a Ti/Au film by electron-beam evaporation to obtain Ohmic contact between Ti and ZnO. The NW then bent by moving the upper nanotip under the direct-imaging condition and the sequential images of the bent NW were captured, following the I-V measurements. The result shows that a bent ZnO NW can produce a piezoelectric electric field (Epz) along and across the NW due to the strain-induced piezoelectric effect and it also shows that a single ZnO NW can be a rectifier simply by mechanically bending it.