Device simulation of ceria-based interfacial switching memristor

Abstract

We present a device simulation on the interfacial switching behavior of ceria (CeO2)-based memristors, considering the migration of oxygen ions and the resulting modulation of Schottky barrier height (SBH). A voltage pulse pulls or pushes oxygen ions depending on its polarity. The SBH can be modulated by the change of the ionic concentration near the contact, which is the mechanism for interfacial switching memristors. A gradual change in conductance can be produced by well-controlled successive pulses, making it suitable for synaptic device applications. Our simulation is composed of two parts. One is calculating the electromigration of oxygen ions to obtain their spatial distribution in the ceria. The other is calculating thermionic current through the SBH to estimate the device's conductance. Our simulation successfully reproduced the previously reported experimental results for the long-term potentiation and depression cycles. We believe that our simulation may provide device engineers with many insights into optimizing the device's performance.