2D perovskite shown promise for advanced memory devices

A Pohang University of Science & Technology (POSTECH) research team has designed a halide perovskite material for next-generation memory devices. Characteristics like low-operating voltage and high-performance resistive switching memory could mean great commercialization potential.

As rapid distribution and transmission of high-quality contents are growing rapidly, it is critical to develop reliable and stable semiconductor memories. To this end, the POSTECH research team succeeded in designing an optimal halide perovskite material (CsPb₂Br₅) that can be applied to a ReRAM device by applying first-principles calculation based on quantum mechanics.

An ideal next-generation memory device should process information at high speeds, store large amounts of information with non-volatile characteristics where the information does not disappear when power is off, and operate at low power for mobile devices.

The recent discovery of a resistive switching property in halide perovskite materials has led to worldwide research to apply it to ReRAM devices. However, the poor stability of halide perovskite materials when they are exposed to the atmosphere has been raised as an issue.

The research team compared the relative stability and properties of halide perovskites with various structures. DFT calculations predicted that CsPb₂Br₅, a two-dimensional layered structure, may have better stability than the three-dimensional structure of ABX₃ or other structures, and that this structure could show improved performance in memory devices.

To verify this result,CsPb₂Br₅, an inorganic perovskite material with a two-dimensional layered structure, was synthesized and applied to memory devices for the first time. The memory devices with a three-dimensional structure of CsPbBr₃ lost their memory characteristics at temperatures higher than 100 °C. However, the memory devices using a two-dimensional layered-structure of CsPb₂Br₅ maintained their memory characteristics at over 140 °C and could be operated at voltages lower than 1V.

Professor Jang-Sik Lee who led the research commented, "Using this materials-designing technique based on the first-principles screening and experimental verification, the development of memory devices can be accelerated by reducing the time spent on searching for new materials. By designing an optimal new material for memory devices through computer calculations and applying it to actually producing them, the material can be applied to memory devices of various electronic devices such as mobile devices that require low power consumption or servers that require reliable operation. This is expected to accelerate the commercialization of next-generation data storage devices."