Keeping heat and electricity from leaking out of integrated circuits becomes so difficult below the 20nm level that everyone from large chipmakers to academic researchers resort to pretty extreme measures to get chips to work right.
There are plenty of research efforts under way to develop reliable ways to build processors with circuits smaller than 14 nm (the current commercial state of the art). MIT researchers say that the circuits should assemble themselves. Others are putting their faith in exotic materials or super-refined versions of current methods that use high-energy ultraviolet light, rather than the tired old visible spectrum.
However, researchers at the University of Rochester have slimmed things down far below even the ambitious targets of those projects. They have found a way to send an electric charge across a circuit one molecule wide while insulating it enough to smother the static and field leakage that make microscale circuits (let alone nanoscale ones) difficult to use.
An inert organic layer one molecule thick insulates the conductor above, whose load capacity can be raised or lowered
by tweaking its hydrogen content.
(Source: University of Rochester)
"Until now, scientists have been unable to reliably direct a charge from one molecule to another," Alexander Shestopalov, an assistant professor of chemical engineering at the University of Rochester, said in a press release. "But that's exactly what we need to do when working with electronic circuits that are one or two molecules thin." His team published a paper describing the process in the April issue of the journal Advanced Materials Interfaces (registration required).
Shestopalov's team linked an organic light-emitting diode (OLED) to a power source using a microscopic strand of inorganic conductor laid across a one-molecule-thick layer of nonreactive organic material, which insulated the conductor from the underlying environment and allowed for a clean flow of electricity to the OLED.
The insulating layer also contained the charge well enough within the conducting layer to let the researchers closely control the flow by manipulating the charge or changing the hydrogen content in the conducting material to increase or decrease the rate of flow to match the volume required by the OLED.
The bi-layer approach counteracts the variability of even heavily insulated single-layer nanoscale conductors or those that function with little or no insulation.
The resulting product is relatively simple to manufacture, and its performance is consistent and predictable, but it is too fragile to be practical with the materials Shestopalov used as a proof point. "The system we developed degrades quickly at high temperatures. What we need are devices that last for years and that will take time to accomplish."
His goal is to create practical, effective materials that combine layers of semi-conductive materials into composites that can be used for high-efficiency solar cells and other photovoltaics and to increase the efficiency of optical devices by shrinking their components to nanoscale using techniques and materials that make it possible to microprint them easily and cost-effectively.