Mar 14, 2012
Understanding nonvolatile memory phenomena in graphene-polymer devices
Researchers at the Seoul National University and Gwangju Institute of science and technology, Korea, have fabricated organic memory devices that feature multilayer graphene film sandwiched between insulating polyimide layers. The array-type structures showed write-once-read-many (WORM) type memory characteristics, with the embedded multilayer graphene film acting as charge trapping layer.
Retention time is an important parameter that is used to evaluate memory performance. In this study, the memory devices showed stable characteristics over 104 s with no significant current fluctuations.
A statistical cell-to-cell uniformity analysis was performed to confirm reliable memory operation. Although the OFF states were relatively broad, the ON states were well separated from the OFF states, allowing the two states to be distinguished.
Using conductive atomic force microscopy, the scientists found that the conduction paths in the low-resistance ON state were distributed in a highly localized area, which was associated with a carbon-rich filamentary switching mechanism.
Full details can be found in the journal Nanotechnology.
About the author
Yongsung Ji is a PhD student at the School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Korea. He is investigating flexible organic electronic devices. Takhee Lee is an associate professor at the Department of Physics and Astronomy, Seoul National University, Korea. His research is focused on molecular and organic electronics, and graphene-electrode optoelectronic devices.