Tunability of voltage pulse mediated memristive functionality by varying doping concentration in SrTiO3

Abstract

The potential applications of memristive devices extend far beyond what can be realized using digital computing with utilization prospects in data encryption and in mobile communication. This necessitates widening the scope of memristive attributes to include the intrinsic variability of the resistive states between cycles for security applications. We demonstrate the ability to controllably influence resistive switching in Nb-doped SrTiO3-based interface memristors of different doping concentrations. We find that the reset switch from low to high analog resistance states is faster than for the reverse process and the switching speed increases with doping. Memristive functionalities, such as resistance window, stochasticity, and nonlinearity, are similarly influenced with doping. We demonstrate that a train of pulses applied in different sequences can encode information, exhibited as distinguishable resistance states, and read by applying a small voltage signal. We attribute these findings to the increased interfacial electric field at higher doping concentrations. The doping concentration is a useful handle to tune the memristive functionality for a wide range of different utilizations, beyond those prevalent today.