The influence of interface contact condition on resistive switching of Au/Nb:SrTiO3 heterojunctions

Abstract

The influence of the interface contact condition on the resistive switching (RS) effects of metal/Nb:SrTiO3 heterojunctions was investigated. Two Au/Nb:SrTiO3 samples with or without in situ substrate cleaning treatment were fabricated. Through comparative analysis of I–V hysteresis and switching performance, it was observed that the RS effect in the heterojunction formed by the in situ cleaned Nb:SrTiO3 substrate was significantly weakened. In addition, the SEM image demonstrates intimate contact between metal and the in situ cleaned substrate. In contrast, the untreated Au/Nb:SrTiO3 interface exhibits poor contact. The poor contact, as confirmed by interface AFM and CAFM images, is responsible for the resistive switching observed. Our research provides an innovative approach to elucidating the mechanism of the resistive switching effect, which will pave the way for better application of the device.

Resistive switching suppression in metal/Nb:SrTiO3 Schottky contacts prepared by room-temperature pulsed laser deposition

“…The role of oxygen vacancies appears relevant also within the interfacial bonds polarization theory [64], as they certainly affect the charge rearrangements dictating the magnitude of the interfacial dipole (supplementary information S13). On the other hand, resputtering and subsurface implantation by energetic metal ions [65] might contribute to make any carbon contamination layer thinner, and to promote intimate metal contact with NSTO [19,28].…”

“…Importantly, switching devices are often found to interact with the environment, as both ambient oxygen and moisture may modulate ϕ B and RS by promoting (or preventing) the excorporation/incorporation of ionic species within the interfacial layer [17,21,[24][25][26][27]. Given the complex nature of the NSTO interfacial layer and of the RS mechanisms, attempts to improve reproducibility and uniformity of electronic transport across M/NSTO SBDs have moved along different directions including in situ NSTO surface cleaning [1,2,28], post-growth thermal treatments [14,29,30], insertion of oxide interlayers [17,19,30], modulation of ambient gases [21,24], and tailored growth of epitaxial electrodes [19]. Such investigations have practical relevance due to the crucial role played by M/NSTO SBDs in several proof-of-concept devices and applications (e.g.…”