1. A nano piezoelectric device comprising:
a lower electrode;
a nanowire extending upward from the lower electrode; and
an upper electrode on the nanowire;
wherein the nanowire includes a conductive wire core and a wire shell surrounding the wire core and including a piezoelectric
wherein the conductive wire core and the wire shell have a PN diode junction connected from the lower electrode to the upper
electrode, respectively, not forming a Schottky contact between the nanowire and the upper electrode.