Potentiation and depression behaviour in a two-terminal memristor based on nanostructured bilayer ZrOx/Au films

The emulation of synaptic functions such as potentiation and depression is of strategic importance for the development of artificial neuromorphic architectures. Memristors can qualitatively reproduce the short-term plasticity behaviour of biological synapses by exploiting the gradual relaxation of resistance levels upon the removal of the switching signals. Various types of memristors based on nanofabricated metal-oxide-semiconductor stacks have been proposed for this purpose. Here we present a different fabrication approach based on cluster-assembled nanostructured zirconia and gold films (ns-Au/ZrOx) deposited in a bilayer planar configuration. This device shows memristive behaviour with short-term memory and potentiation/depression. The observed relaxation can be described by a stretched-exponential function. Furthermore, the characteristic time of the short-term phenomena dynamically changes under repeated pulses application. Our nanostructured device is characterised by a substantially larger conductive path length with respect to other nanoscale memristive devices; the use of a zirconia nanostructured film makes the device compatible with neuronal cell culture.