1 research outputs found
Unravelling Resistive Switching Mechanism in ZnO NW Arrays: The Role of the Polycrystalline Base Layer
The
physical mechanism involved in resistive switching phenomena
occurring in devices based on ZnO nanowire (NW) arrays may vary considerably,
also depending on the structure of the switching layer. In particular,
it is shown here that the formation of a ZnO base layer between the
metallic catalyst substrate and the NW, which is typical of CVD-grown
ZnO NW arrays, should not be neglected when explaining the switching
physical mechanism. The structural and electrical properties of this
layer are investigated after the mechanical removal of NWs. Electrical
measurements were performed in the presence of NWs and, after their
removal, showed that the base alone exhibits resistive switching properties.
The proposed switching mechanism is based on the creation/rupture
of an oxygen vacancies conductive path along grain boundaries of the
polycrystalline base. The creation of the filament is facilitated
by the high concentration of vacancies at the grain boundaries that
are oriented perpendicularly to the electrodes, as a direct consequence
of the ZnO growth along the <i>c</i>-axis of the wurtzite
lattice