Light-activated Multilevel Resistive Switching Storage in Pt/Cs₂AgBiBr₆/ITO/Glass Devices

High-density Cs₂AgBiBr₆ films with uniform grains were prepared by a simple one-step and low-temperature sol-gel method on indium tin oxide (ITO) substrates. An explicit tristate bipolar resistance switching behavior was observed in the Pt/Cs₂ AgBiBr₆/ITO/glass devices under irradiation of 10 mW/cm² (445 nm). This behavior was stable over 1200 s. The maximum ratio of the high and low resistance states was about 500. Based on the analysis of electric properties, valence variation and absorption spectra, the resistive switching characteristics were attributed to the trap-controlled space charge-limited current mechanism due to the bromine vacancies in the Cs₂AgBiBr₆ layer. On the other hand, it is suggested that the ordering of the Schottky-like barrier located at Pt/Cs₂AgBiBr₆ affects the three-state resistance switching behavior under light irradiation. The ability to adjust the photoelectrical properties of Cs₂AgBiBr₆-based resistive switching memory devices is a promising strategy to develop high-density memory.