In yet another approach to using scanning probe microscopy to build better computer memories (for the previous one, see Scanning probe tip arrays for denser, faster, cheaper memories through nanotechnology), nanotech draws and erases lines three nm wide. From “Tiny Etch-a-Sketch” in Technology Review, written by Mason Inman:
It may be the world’s tiniest Etch-a-Sketch. Researchers have demonstrated a new technique that could be used to create rewritable logic circuits and denser computer memory. Using an atomic force microscope (AFM), the researchers were able to draw nano-sized wires and dots that could be repeatedly erased and written.
Led by Jeremy Levy of the University of Pittsburgh, the researchers used an AFM tip like a pencil, drawing electrically conductive paths—which act like metallic wires—on a special material. The lines were as thin as three nanometers, making them considerably narrower than the lines that can be drawn using electron beam lithography—one of the most precise techniques for etching devices out of silicon.
The researchers used a two-layer material developed by Jochen Mannhart’s group at the University of Ausberg, in Germany. The base is made of a strontium titanate crystal, with a thin layer of lanthanum aluminate on top. The interface between the two materials can be switched from insulating to conducting by applying a voltage across the interface.
The research was published in Nature Materials (abstract)