  The intrinsically rectifying-resistive switching (IR-RS) has been regarded as
an effective way to address the crosstalk issue, due to the Schottky diodes
formed at the metal/oxide interfaces in the ON states to suppress the sneak
current at reverse biases. In this letter, we report for the first time another
type of IR-RS that is related to the built-in homojunction. The IR-RS study was
usually limited to macroscopic samples with micron-order pad-type electrodes,
while this work is on NiO nanodots fabricated with ultrathin
anodic-aluminum-oxide templates and acting as nanoscaled analogs of real
devices. The NiO nanodots show high storage density and high uniformity, and
the IR-RS behaviors are of good device performances in terms of retention,
endurance, switching ratio and rectification ratio. The feasibility of the
IR-RS for selection device-free memory application has been demonstrated, by
calculating the maximum crossbar array size under the worst-case scenario to be
3 Mbit.
