Nanowerk August 15, 2022
In this review article an international team of researchers (Germany, Switzerland) addressed resistive switching devices operating according to the bipolar valence change mechanism (VCM). VCM cells consist of three parts: an electronically active electrode (AE), a mixed ionic-electronic conducting (MIEC) layer consisting of a nanometer-scale metal oxide, and an ohmic counter electrode (OE). They provided detailed insights into the status of understanding of these devices as a fundament for their use in the different fields of application. The review covered the microscopic physics of memristive states and the switching kinetics of VCM devices. Electroforming, a process often required prior to resistive switching, is described in terms of electronic initialization and subsequent changes in chemistry, structure, and conductivity. The switching process is discussed in terms of switching polarity, geometry of the switching region, and spectroscopic detection of the valence changes. The review concludes with a treatment of the highly relevant reliability issues and a description of the failure mechanisms, including mutual trade-offs…read more. TECHNICAL ARTICLE