Relaxation oscillations in circuits containing sandwich switches based on vanadium dioxide

Abstract

ABSTRACTElectrical switching with an S-shaped I–V characteristic is studied in metal/oxide/metal structures based on vanadium oxide thin films fabricated by electrochemical oxidation. This switching effect is associated with the metal–insulator phase transition in VO2, and the channels consisting of vanadium dioxide are formed in the initial anodic films during the process of electroforming. An expression for the relaxation oscillation frequency, as a function of the external circuit RC factor and I–V curve parameters, is obtained. It is shown that the experimental data on the frequency–capacitance dependence match well this theoretical relation. Applied aspects of the obtained results, particularly concerning oscillatory neural networks and frequency-output sensors, are discussed.