The next step is for researchers to harvest the tiny wires by dissolving or rubbing them off of the substrate and densely packing them on a piece of silicon to build a memory device. (According to the researchers, the details of this process still need to be worked out.) Once arranged, the wires will be jolted into an amorphous phase (the equivalent of a one in computer logic) or back into a crystalline state (the equivalent of a zero) with an electric pulse so that data can be stored. “Eventually, what we want is a very high density of nanowires so we can make the best use of their storage capabilities,” says Agarwal. “The challenge now is how to put them together.”
Spike Narayan, senior manager of nanoscience and technology at IBM’s Almaden Research Center, hopes that these findings will help encourage the development of new memory devices that use phase-changing materials. “This research clearly shows that if we invest in this technology, it will be around in 20 years,” he says.
But Narayan also notes that several more years of research are needed before this technology will be viable for consumer products. “The major challenge is not growing the nanowire: it’s growing it where you want it,” he says. “How do you pick and place [an individual wire] where you want it? Currently, there are no good ways to do this.”
Agarwal agrees. “We’ve shown a very important concept, and now we have to put it into practical use,” he says.