Molecular electronic device shows promise

Thanks to a team of materials scientists at Northwestern University, molecular electronics may be one step closer to reality. The researchers, led by Mark Hersam, assistant professor of materials science and engineering, have become the first to measure a unique and versatile nanoelectronic effect — called resonant tunneling — through individual molecules mounted directly on silicon.

The findings were published online Nov. 1 by Nano Letters, a publication of the American Chemical Society. The article will appear in print on the cover of the journal’s January 2004 issue. “This work represents the first experimental realization of a molecular resonant tunneling device on a semiconductor,” said Hersam. “The device works at room temperature and on silicon, which are important features that suggest that it can be made compatible with conventional silicon microelectronics. It’s easier to make inroads if you complement current technology rather than replace it.”

Silicon microelectronics has undergone relentless miniaturization during the past 30 years leading to dramatic improvements in computational capacity and speed. At the most fundamental limit, individual molecules have been envisaged as functional electronic devices. When interfaced with conventional circuitry, resonant tunneling devices allow improved efficiency and reduced power consumption in computer architectures.

Resonant tunneling also may allow individual molecules to be detected and identified, thus creating future opportunities for high sensitivity sensors.