By JOHN MARKOFF
Published: October 20, 2003 : The New York Times
A team of university researchers has constructed an electronic memory circuit from disordered arrays of electronic clumps of gold atoms, according to a report to be published today in the Journal of the American Chemical Society.
The advance, made by researchers at Rice University, North Carolina State University and Pennsylvania State University, is based on one of several approaches that are being pursued to create a microelectronic technology on a much smaller scale than today's silicon chips.
In the new field, known as molecular electronics, the researchers have succeeded in creating tiny switches from molecules and atoms. They are now searching for ways to assemble the vast arrays of the switches to serve both as memory and computing devices.
In one approach, being pursued by researchers at Hewlett-Packard and the University of California at Los Angeles, a mesh of extremely fine wires is created with a switch at the points where wires cross.
In contrast, the team led by James Tour, a chemist at Rice University, has opted to build circuits from molecules that are randomly laid out between larger contact points.
By repeating tiny electrical pulses between adjacent contact points, the researchers were able to create regions they referred to as nanocells, which would function both as memory and as computer logic circuits.
So far, the researchers have created circuits that are about 10 times as dense as silicon chips, though they switch on and off far more slowly, Mr. Tour said.
Even if it is not possible to increase the switching speed of the new circuits, they could potentially be used in applications where the stored information is permanent or changes infrequently.
The researchers said their self-assembling circuits performed in some ways like the neural circuits in the human brain, where pathways tend to persist even if they are not used frequently.
They said they thought there were several types of physical phenomena creating the switching effects, storing ones and zeros in their laboratory for more than a week at a time.