October 3, 2012
Graphene: Flexible, Transparent Memory On Its Way To Reality
Lee Rannals for redOrbit.com — Your Universe Online
Graphene is making headlines more and more as researchers find new ways to expand its many uses. Now, researchers from Rice University are looking to the material, as well as silicon oxide, as a new form of flexible, transparent memory.
The scientists were able to design transparent, two-terminal, three-dimensional computer memories on flexible sheets using silicon oxide and graphene.
The technique is based on the switching properties of silicon oxide, which was made possible through a breakthrough discovery by Rice in 2008.
The team wrote in the journal Nature Communications that they are making highly transparent, nonvolatile resistive memory devices based on the revelation that silicon oxide can be a switch.
At just 5 nanometers, a channel can be created to extend memory beyond Moore's Law, which predicts computer circuitry will double in power every two years.
Manufacturers are finding physical limits on current architectures when trying to fit millions of bits on small devices. Currently, electronics are made with 22 nanometer circuits.
Combining silicon and graphene enables the scientists to extend the possibilities of where memory can be placed. The devices could not only have potential for facing the harsh conditions of radiation, but also could be able to withstand heat of up to about 1,300 degrees Fahrenheit.
Dr. James Tour, a chemist who led the research along with physicist Douglas Natelson, told redOrbit that the technology would have a few advantages over current memory technologies.
"Memory today is not transparent, hence cannot be used on glass while retaining the see-through properties," Tour told redOrbit. "Second, memory today does not work well on flexible substrates, like plastic."
He said in future devices, engineers would be able to substitute the present-day transistors used in memory like Flash memory, with their silicon oxide design.
Tour said the devices are transparent because they are based on silicon oxide, which is the same thing as in glass.
"But we need transparent wires to wire them together and bring in the needed voltages and record the currents," he told redOrbit over email. "Graphene, being transparent, is being used as the wiring for both the input and output electrodes on the plastic substrates. On the glass substrates, we use indium-tin-oxide (ITO), a transparent metallic electrode for the input and graphene on top for the output."
He said the lab is building crossbar memories with embedded diodes to better manipulate control voltages.
"We've been developing this slowly to understand the fundamental switching mechanisms," Tour said in a statement. "Industries have flown in and looked at it, but we're doing basic science here; we don't package things nice and pretty, so what they see looks rudimentary.
"But this is now transitioning into an applied system that could well be taken up as a future memory system," he said.