A Reliable Triple-Level Operation of Resistive-Gate Flash Featuring Forming-Free and High Immunity to Sneak Path

Reliable BiI3-Based Resistive Random-Access Memory Devices with a High On/Off Ratio

“…Resistive random-access memory (RRAM), in which data bits are saved by the different resistance states, has been extensively studied owing to its simple metal/insulator/metal structure, low operating power, high responsive speed, and multistate data storage. − RRAMs are also candidates for synapse devices for neuromorphic computing, in which the data processing and memorizing can be achieved in parallel. , The transition-metal oxides such as HfO 2 and ZnO have been intensely investigated as resistive switching layers for RRAM devices and have been demonstrated as having excellent performance. , Halide-based perovskite with its fascinating properties, including a tunable and direct band gap, a superior absorption coefficient, low exciton binding energy, and high carrier mobility, is considered to be a promising material in various applications such as photovoltaics, photosensors, lasers, transistors, and light-emitting diodes. − In particular, it can also be used as a resistive switching layer in RRAMs because of its ion migration mobility, the electrical hysteresis effect, low processing temperatures, low fabrication cost, and enhanced mechanical bending endurance. − There are several reports which have demonstrated halide perovskite-based RRAMs with outstanding performance of multistate data storage, pico-watt operating power, nanosecond response speed, and photo-assisted writing. ,,, The critical issue for the commercialization of halide perovskites is the inclusion of toxic elements and structural instability. − Therefore, nontoxic halide-based materials such as bismuth-based perovskites have recently been developed, such as CsSnI 3 , Cs 3 Bi 2 I 9 , and Rb 3 Bi 2 I 9 , and utilized as resistive switching layers. − Among them, the precursors of bismuth-based perovskites, bismuth-iodide (BiI 3 ), have been widely used in X-rays and photodetectors and in solar cells, owing to their heavy elemental composition and strong absorption. − BiI 3 has a rhombohedral crystal structure with a high and wide absorption spectrum. With the advantages of anisotropic transport, low intrinsic carrier concentration, environmental friendliness, and structural stability, BiI 3 is a promising material for use in resistiv...…”