Rectifying junction in a single ZnO vertical nanowire

The authors introduce dopants in vertically grown single crystalline ZnO nanowires in a controlled manner. A section of the nanowires is doped with aluminum as donor during crystal nucleation, resulting in n-n+ junction. Current-voltage characteristics of these single nanowire junctions via scanning tunneling microscopy and mercury-probe methods are asymmetric, displaying rectifying behavior. By inversing the junction during the growth or by introducing lithium as acceptor to form a n-p junction, the directionality of current flow in the nanowires becomes reversed. The single nanowire diode junctions are very stable in ambient condition and hence open up a new dimension in nanoelectronics.