Digital memory given graphene boost

The University of Nebraska-Lincoln research team has engineered and tested improvements in the performance of a memory structure known as a ferroelectric tunnel junction - effectively creating the next-generation of high-speed, high-capacity RAM.

RAM, which can be both dynamic (DRAM) and static (SRAM), is a form of computer memory accessed randomly within a computer or printer, for example.

The researchers, whose study has been published in the journal Nature Communications, claimed their ferroelectric tunnel junction features a ferroelectric layer 100,000 times thinner than a sheet of paper - so thin that electrons can ’tunnel’ through it.

According to reports, the research team are the first to design a ferroelectric junction with electrodes made of graphene - an atom-thick carbon compound often dubbed as an emerging ’wonder material’.

While its amplified conductivity makes graphene well-suited for small-scale electronics, the research team’s primary interest looked at how it accommodated nearly any type of molecule - specifically, ammonia - that was placed between it and the ferroelectric layer.

A junction’s polarity determines its resistance to tunnelling current, with one direction allowing current to flow and the other strongly reducing it, the researchers said.

Further investigations uncovered how the research team’s graphene-ammonia combination increased the disparity between these ’on’ and ’off’ conditions, a highly sought-after outcome that improves the reliability of RAM devices and allows them to read data without having to rewrite it.

“This is one of the most important differences between previous technology that has already been commercialised and this emergent ferroelectric technology,” said Alexei Gruverman, who co-authored the study.