LAUSR

The kinetics of current at switching of the VO2 based glass-ceramics samples from a state with high resistance (the off-state) to a state with low resistance (the on-state) and vice versa was studied. The delay of the transition from off-state to on-state, when a switching voltage U0 is applied to a sample, is related to the time tdon required to heat a sample to the metal-semiconductor phase transition temperature in VO2. The delay time tdon decreases with the increase of U0. It is shown that the calculated dependence of tdon on the voltage U0, obtained with the simplified heat balance equation of a sample and the “critical temperature” model, is in good conformity with the experimental data. It was found that the delay of reverse transition from the on-state to the off-state controls the conductive channel, within which the crystallites of VO2 are in the metallic phase. The delay time tdoff of this transition determines the time during which, after turning off the voltage U0, a conductive channel exists in a sample. The value of tdoff increases with the increase of U0. The reason for this behavior is the expansion of conductive channel with the increase of U0. As a consequence, takes place the increasing number of VO2 crystallites in the metallic phase. Therefore, tdoff increases due to an increase in the time required for dissipation of the heat released during the transition of the VO2 crystallites from the metallic phase to the semiconducting phase.