For next-generation semiconductors, 2D tops 3D

Date:
July 13, 2020
Source:
Pohang University of Science & Technology (POSTECH)
Summary:
A research team designs a halide perovskite material for the next-
generation memory device. Commercialization is accelerated for next-
generation data storage device via low-operating voltage and high-
performance resistive switching memory.



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To this end, POSTECH research team has developed a memory device using
a two- dimensional layered-structure material, unlocking the possibility
of commercializing the next-generation memory device that can be stably operated at a low power.

POSTECH research team consisting of Professor Jang-Sik Lee of the
Department of Materials Science and Engineering, Professor Donghwa
Lee of the Division of Advanced Materials Science, Youngjun Park,
and Seong Hun Kim in the PhD course succeeded in designing an optimal
halide perovskite material (CsPb2Br5) that can be applied to a ReRAM*1
device by applying the first-principles calculation*2 based on quantum mechanics. The findings were published in Advanced Science.

The 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 the resistive switching property in halide
perovskite materials has led to worldwide active research to apply them
to ReRAM devices.

However, the poor stability of halide perovskite materials when they
are exposed to the atmosphere have been raised as an issue.

The research team compared the relative stability and properties of
halide perovskites with various structures using the first principles calculation2.

DFT calculations predicted that CsPb2Br5, a two-dimensional layered
structure in the form of AB2X5, may have better stability than the three-dimensional structure of ABX3 or other structures (A3B2X7, A2BX4),
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 DEGC.

However, the memory devices using a two-dimensional layered-structure
of CsPb2Br5 maintained their memory characteristics over 140 DEGC 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."

========================================================================== Story Source: Materials provided by Pohang_University_of_Science_&_Technology_(POSTECH).

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ju‐Hyun Jung, Seong Hun Kim, Youngjun Park, Donghwa Lee,
Jang‐Sik Lee. Metal‐Halide Perovskite Design for
Next‐Generation Memories: First‐Principles Screening
and Experimental Verification. Advanced Science, 2020; 2001367 DOI:
10.1002/ advs.202001367 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200713120026.htm

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