Synthetic Powder-Based Thin (<0.1 μm) Cs₃Bi₂Br₉ Perovskite Films for Air-Stable and Viable Resistive Switching Memory

Here, we report on the resistive switching performance of a thin Cs₃Bi₂Br₉ perovskite film with a thickness of <0.1 μm, enabled by synthesized Cs₃Bi₂Br₉ powder. X-ray diffraction (XRD) confirmed that the synthesized powder was crystallized in a trigonal phase with a space group of P3̅m1. Compared to the precursor mixture of CsBr and BiBr₃, the synthesized powder improved solubility in dimethyl sulfoxide (DMSO), leading to a conformal coating on an indium-doped tin oxide (ITO) substrate. The Ag/Cs₃Bi₂Br₉/ITO devices exhibited a bipolar resistive switching behavior, where a forming step occurs at about +0.5 V prior to reliably repeated switching. As a result, an operational voltage as low as +0.44 V, endurance as high as ∼2000 cycles, and retention time of about 10⁴ s were observed, along with a multilevel storage capability as confirmed by changing the compliance currents for the SET process. A study of the conduction mechanism with a Au electrode revealed that Ohmic conduction is dominated via ion migration such as the bromide ion in Cs₃Bi₂Br₉. The bipolar resistive switching characteristic was maintained even after storing the devices for more than one month in ambient conditions under a relative humidity of 50%, which is beneficial for viable electronic applications.