Molecular Electronics Close to Reality

Now, however, researchers and engineers have been evaluating another exciting way to utilize individual molecules, as functional electronic devices.

A group of engineers at Northwestern University (Evanston, IL, USA) has become the first to accurately align multiple kinds of molecules on a silicon surface at room temperature--a significant step toward the reality of molecular electronics.

"We have demonstrated a strategy for intentionally positioning molecules, which is necessary for the construction of nanoscale systems such as molecular transistors or light-emitting diodes,” said Dr. Mark C. Hersam, assistant professor of materials science and engineering, who led the research team. "Our process works at room temperature and on silicon, which suggests that it can be made compatible with conventional silicon microelectronics. Ultimately, we want to integrate with current technology, thus creating a bridge between microelectronics and nanoelectronics.”

The data from the study show patterning on a magnitude of 10,000 times smaller than that of microelectronics. The study was published in the September 27, 2004, issue of the journal Applied Physics Letters (APL).

The nanofabrication method, called multistep feedback-controlled lithography, is useful for a host of essential studies and for the testing and building of prototype nanoscale devices that could be utilized in potential technologies ranging from biomedical diagnostics to consumer electronics.

"Previously we were working with single molecules on silicon,” said Dr. Hersam. "This new process enables us to build more complex structures. Plus, the technique is general and can be used with many different molecules, which increases its potential.”

The investigators verified their process by using a tailored ultrahigh-vacuum scanning tunneling microscope. With this technique, they created chains consisting of styrene and a molecule called TEMPO, and are now researching the electronic characteristics of this unique nanostructure.




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