Memristive behavior in SnO2 wires guided by surface oxygen vacancy motion and H2O molecules: A study

We present a study of an anomalous electrical behavior observed in SnO2 memristor devices based on nanowire networks previously studied by our group. This behavior shows strongly depend on the surface–environment interaction of the nanowires. To enhance/evidence it, we built a device based on a single microwire with higher interaction to ambient air. This device proved to be a memristor in cyclic voltammetry. Based on the literature and voltammetry data, we propose a model to describe that behavior based on the formation/rupture of surface conductive paths formed by water molecules adsorbed in oxygen vacancies and the changes caused by these dynamics in the device's equivalent circuit. We also enhance the behavior in nanowire networks, producing devices with a higher exposure level of the nanowires to the environment. Additionally, these network devices showed potential for application in resistive memories, with an ON/OFF ratio of 22.2 and retention of 1400 s.