Storage site

Dror Sarid

Data density is what the latest organic chemistry is all about. Picture the information stored on 1500 of today's compact disks enclosed in a single CD. University of Arizona optical scientists are applying new probe microscopy techniques to organic materials to come up with the next generation of very fast, low-cost, and compact memory devices.

Ghassan Jabbour

Nanometer-scale technology is where data storage is heading according to Dror Sarid and Ghassan Jabbour and their colleagues. They are creating nanotech inexpensive organic films that will ultimately be written to and read from a probing micro-electromechanical systems (MEMS) device.

			The tunneling atomic force microscope, or "tuna", is instrumental in writing information into clusters of molecules within nano-thick organic films. (Photo: Courtesy of Dror Sarid)

Present optical CDs can hold about 500 megabits of data per square inch, while a magnetic hard disk drive holds 32.6 gigabits per square inch. The industry goal is a device that can store one terabit per square inch, that's about 1000 gigabits of storage capacity. "There is no way you can obtain this storage density unless you develop nanotechnology," Sarid explains. "Although conventional data storage can contain a huge amount of information, it has two problems," he continues, "One, because it is mechanical, you have to wait several milliseconds to retrieve what you wrote. I mean, really, you can blink during the time it takes the system to read the disk. That's one bottleneck. And, two, while there are other 'random access memory' or RAM, technologies that can be read a thousand times faster than data on a hard disk, they cost 10 times more than hard-disk storage. High cost storage capacity has limited RAM technology use."

Sarid and his group demonstrated self-assembly of molecular electronics with STM (scanning tunneling microscopy) in 1992. STM technology fabricates structures on the nanometer scale. (Photo: Courtesy of Dror Sarid)

The Arizona team is building on an idea first mooted by IBM and Stanford University researchers to combine the affordability of hard-disk storage technology with the speed of RAM. They have already shown how a MEMS probe can deliver pulses of electric current at its tip making a cantilevered tip "tap" on an organic film surface. The contact points can thus be "written" by inducing a chemical change in clusters of organic molecules at each point. Sarid suggests that, "In principle, one should have no trouble in making a million cantilevers operate in parallel in the MEMS probe. After all, Intel's Pentium processor has millions of transistors, and our device is much simpler than a transistor." For those curious about the actual materials being investigated, Sarid adds that, "We cannot at this point in time discuss the composition of the organic media."