Nucleation theory of threshold switching in vanadate–glass devices

Abstract

On the basis of a heterogeneous model, a theory is developed, providing a description of the off-branch and the straight linear part of the on-branch of the I–V characteristics ofthreshold vanadate switches. The theory is based on the electrostatic influence of the electric field on the rate of nucleation in the amorphous volume of the switch and gives an exponential run to the I–V characteristics for the pre-breakdown region of voltages. As a result, a parabolic dependence of the threshold voltage on the temperature is obtained and, simultaneously, the bipolar nature of the threshold switching in the amorphous devices is predicted. The exponential decrease in the delay time with an increase of electric field is found, a behaviour that does not depend on the direction of the field. Moreover, the possibility of monopolar threshold switching is predicted. Good agreement is established between the experimental results and the theoretical dependences.