Cornell teams to probe molecular and nanoscale technology

Two groups of Cornell University researchers have been awarded US defence agency contracts aimed at exploring a new generation of electronics technology at the molecular and nanoscale levels.

The goals of the two programs are to investigate the possibility of developing new devices that could ultimately lead to huge increases in data storage and processing speed.

At the molecular level, George Malliaras, assistant professor of materials science and engineering, has been awarded a four-year, $400,000 contract by the Defence Advanced Research Projects Agency (DARPA).

His research into understanding how to make molecules work like switches is part of a larger multi-disciplinary DARPA program, with the goal of demonstrating the feasibility of building functional molecular electronic devices.

DARPA’s hope, according to Malliaras, is to develop molecular electronics devices that would leapfrog current silicon chip technology by increasing the number of transistors on a chip to the hundreds of millions. A Pentium II processor, one of the densest chips in use today, contains 7.5 million transistors.

Malliaras’s project, which is Cornell’s entry into molecular electronics research, is to investigate the electrical properties of individual molecules.

To do this, he will build test structures that will contain a very small number of molecules between two metal electrodes.

The measurements will take place at a probe station integrated with a cryostat and electrical characterisation equipment that can measure down to 400 ato-Amperes (aA), which is about 5 electrons a second flowing through the molecules.

The cryostat will keep the molecules at temperatures as low as 4 degrees Kelvin.

In theory, molecular electronics research could lead to circuits in which each element of a system, such as a transistor, diode or conductor, would be replaced by an individual molecule.

Such molecular microchips, Malliaras said, could provide greatly improved computing speed and immense storage with a minimum of power demands, leading to such applications as a camera that could store millions of pictures or a watch with the computing power of a desktop PC.

However, Malliaras believes that molecular electronics ‘is a fairly long shot’ that could take a decade or more to develop.

At the nano scale, Robert Buhrman, professor of applied and engineering physics at Cornell, together with Dan Ralph, associate professor of physics, and colleagues at four other universities have been awarded a contract by the US Army Multidisciplinary University Research Initiative (MURI) to study and exploit the spin property of electrons.

At the heart of the study of spin manipulation and spin interactions, said Buhrman, is the future hope of using wave function and spin instead of, or in addition to, electric charge to maintain and process stored information, a technology called quantum manipulation.

‘Magnetics and spin have the possibility of replacing silicon memory with magnetic memory integrated onto a silicon chip,’ said Buhrman. ‘Beyond that, magnetics and spin phenomena have the possibility of implementing quantum computing, an extremely long range and challenging program.’

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