Researchers at the University of California, Los Angeles, and one of the largest manufacturers of computer memory, Samsung, have created a new kind of flash memory that uses graphene—atom-thick sheets of pure carbon—along with silicon to store information.
Incorporating graphene could help extend the viability of flash memory technology for years to come, and allow future portable electronics to store far more data.
Chipmakers pack increasing amounts of data in the same physical area by miniaturizing the memory cells used to store individual bits. Inside today’s flash drives, these cells are nanoscale “floating gate” transistors. Recent years have seen the rapid miniaturization of flash cells, enabling, for example, the iPhone 4 to store twice as much data as the iPhone 3. But below a certain cell size, silicon becomes less stable, and this has the potential to halt the march of miniaturization.
Graphene-based technology like that demonstrated the UCLA team and Samsung could let flash memory continue shrinking. The group’s prototypes devices are described online in the journal ACS Nano.
“We’re not totally replacing silicon but using graphene as the storage layer,” says Augustin Hong, who worked on the devices at UCLA and is now a research staff member at IBM’s Watson Research Center. “We’re using graphene to help extend the capabilities of the conventional technology.”
The graphene flash memory prototypes can be read and written to using less power than conventional flash memory, and they can store data more stably over time, even when miniaturized. The UCLA researchers have also demonstrated that they meet the industry standard of 10-year projected data retention—today’s flash memory does too, but future versions may not. Most important, the graphene memory cells don’t electrically interfere with one another—a problem with conventional flash cells as they are made smaller that can cause them to malfunction.
Other researchers are working on radical new kinds of computer memory that promise to hold more data. However, many of these alternatives require exotic materials and totally new manufacturing processes. Replacing silicon with graphene in flash memory cells could provide a simpler, more practical solution, at least in the short term.