Oxygen vacancy driven resistive switching in SrTiO3/Si(001) heterostructures due to an electronic mechanism

Abstract

Resistive switching (RS) has been extensively studied for its potential applications in non-volatile memory and neuromorphic devices. RS in oxides is closely linked to the presence of oxygen vacancies, which play a crucial role in its underlying mechanism. One of the most widely explored RS mechanisms involves the migration of oxygen ions within the oxide. In this study, we investigate the RS behavior of strontium titanate (SrTiO3) thin films grown directly on Si(001) substrates using oxide molecular beam epitaxy. We examine the dependence of the RS behavior on the oxygen vacancy concentration and substrate type. We find that the concentration of oxygen vacancies in SrTiO3 is the primary determinant of the RS behavior. We simulate the band bending at the heterostructure, successfully reproducing the salient I–V characteristics observed experimentally. Our model considers only electronic effects and incorporates a layer of oxygen vacancies that drifts under an applied voltage bias. We demonstrate that both the conduction-band offset between Si and SrTiO3, and the oxygen vacancy distribution are critical in determining RS behavior and reproducing the experimental I–V characteristics.