Memristors are considered exciting for more than their potential to create brain-like computers. Unlike flash memory, they're fast. Unlike random access memory (RAM), they remember their state – whatever information they held – when they lose power. They also require less energy to operate, rarely crash, and are immune to radiation. The trouble is that they are two-terminal electronic devices, which results in them being tunable only through changes in the voltage applied externally.
The team at Northwestern transformed memristors from two-terminal to three-terminal electronic devices, thereby allowing their use in more complex electronic circuits and systems. The normal memristor setup as two-terminal devices allows only limited control over how electrical current flows through the system, but the third electrode used by the Northwestern researchers can act as a gate, finely controlling the resistance.
They achieved this by using a nanomaterial semiconductor called molybdenum disulfide, which has its "grains" of atoms arranged in a different direction to the memristors. A grain boundary sits between the molybdenum disulfide sheet and the metal electrode, acting as a kind of interface for the atoms. "These grain boundaries influence the flow of current, so they can serve as a means of tuning resistance," co-author Mark Hersam said.
The grain boundary moves when a large electric field is applied on the memristor, which causes a change in resistance. And that, Hersam noted, makes possible a new level of function and complexity that could lead to brain-like computing. "We are now actively exploring this possibility in the laboratory," he said.
A paper describing the research was published in the journal Nature Nanotechnology.
Source: Northwestern University
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