New devices based on nanowire could improve computer memory and can operate for days without the need to recharge, according to a recent study at National Institute of Standards and Technology (NIST).

These nanowires form the basis of memory that is non-volatile, holding its contents even while the power is off-just like the flash memory in USB thumb drives and many mp3 players. The nascent technology is based on silicon formed into tiny wires, about 20 nanometers in diameter.

Researchers are working to optimize nanowire-based charge-trapping memory devices, potentially illuminating the path to creating portable computers and cell phones that can operate for days between charging sessions.

They are also studying such nanowire devices as the possible basis for next-generation computer memory as they hold the promise to store information faster and at lower voltage.

Nanowire memory devices also hold an additional advantage over flash memory, which despite its uses is unsuitable for one of the most crucial memory banks in a computer: the local cache memory in the central processor.

Cache memory stores the information a microprocessor is using for the task immediately at hand, says NIST physicist Curt Richter. It has to operate very quickly, and flash memory just isn't fast enough. If we can find a fast, non-volatile form of memory to replace what chips currently use as cache memory, computing devices could gain even more freedom from power outlets-and we think we've found the best way to help silicon nanowires do the job.

The team, which is using a combination of software modeling and electrical device characterization, explored a wide range of structures for the dielectrics - thin layers of material surrounding nanowires that store electrical charge. Based on the understanding they gained, Richter says, an optimal device can be designed.

These findings create a platform for experimenters around the world to further investigate the nanowire-based approach to high-performance non-volatile memory, says Qiliang Li, assistant professor of Electrical and Computer Engineering at George Mason University. We are optimistic that nanowire-based memory is now closer to real application.

Electronics