Breakthrough in Nanomachining and Organic Molecular Breakdown

A group of engineering researchers recently discovered a technique for building nanoscale devices, based on the dielectric breakdown of liquid organic molecules. This process is an electrical breakdown of a dielectric - electrical insulator - whereupon being stressed beyond its dielectric strength, resulting in the sudden transition of part of the dielectric material from an insulating state to a highly conductive state.

"Understanding dielectric properties of very thin layers plays a critical role in next-generation electronic devices," said Ajay Malshe, professor of mechanical engineering at the University of Arkansas. "In the past 10 years, the machining process in conductive materials for these devices has been scaled down to the micro level - between 3 and 10 micrometers. With this project, we demonstrated dielectric breakdown for the first time at the nanolevel."

These new types of nanoscale electronic components could have practical applications like electrical switches, logic elements, frequency mixers and nanoscale inductors, as well as in detecting DNA and precisely controlling drug release.

"This understanding is an important step toward achieving reproducibility, reliability and repeatability when machining at sub-20 nanometer scales, which is vital for the realization of nanoscale active systems," said Kamlakar Rajurkar, professor of industrial engineering and management systems at the University of Nebraska-Lincoln.

The new nanomachining technique, using an electric discharge, characterized by the formation of an electric spark and possibly an electric arc through the material, allowed the engineers to place a cathode tip - a negatively charged electrode acting as a point - against an anode plane - a positively charged plane - and sandwich the organic molecules between them.

When a voltage is applied to gap, this generates an intense electric field in the organic molecular medium, an integral part of the machining setup, a process they called nanoscale electric discharge machining, or nanoEDM.

"The success of nanoEDM will allow industry to work on a variety of electrically conducting and semi-conducting materials in a non-vacuum environment," said Kumar Virwani, a recent engineering doctoral graduate and co-author of the study. "It will be instrumental for a wide range of emerging applications."