Write voltage-dependent transport mechanisms in Pt/BaTiO3/Nb:SrTiO3 ferroelectric tunnel memristors

Abstract

Here, we demonstrate write voltage-dependent electron transport mechanisms in Pt/BaTiO3/Nb:SrTiO3 ferroelectric tunnel memristors. Tunable resistances associated with a large resistance variation were observed at room temperature. It is found that the electron transport mechanism of the device depends not only on the polarity, but also on the magnitude of the write voltage. For positive write voltages, the memristor holds a low resistance state whereas for low negative write voltages, the memristor exhibits a high resistance state. However, an enhanced negative write voltage causes a transition of the transport behavior from direct tunneling into Schottky thermionic emission. The ferroelectric polarization modulation of electron accumulation or depletion at the ferroelectric/semiconductor interface and the resultant change of the interface barrier width/height under the external voltages are proposed to be responsible for the write voltage-dependent electron transport mechanisms.