Scientists at Northwestern University in Evanston, Ill., have found a new application for atomic force microscopes: fabricating nanoelectronic circuitry.
Researchers at the university discovered that the lab tool could transfer molecules with extremely high precision onto a substrate on a scale 1000 times smaller than microcircuits.
An atomic force microscope operates by using a silicon nitride stylus to trace the contour of a surface. Circuitry in the tip allows it to follow the topography of a surface and to render a three-dimensional image in atomic detail. But when this occurs, the tip has a tendency to attract moisture from the air, forming a small column of liquid. The scientists realized they could transfer a compound called octadecanethiol through this tiny capillary of water onto the substrate. The sulfur in the compound helps it adsorb to the substrate.