Writing electrical circuits using an AFM

Electronic materials

April 22, 2008

An AFM tip can be used to write and erase nanoscale electronic structures in oxide materials much like an Etch-A-Sketch toy. (Courtesy of Jeremy Levy.)

Nanoscale wires and conducting regions can be simply written and erased in oxide materials using a conducting atomic force microscope (AFM) tip, researchers have found [Cen et al., Nat. Mater. (2008) 7, 298].

The work makes use of a recent discovery that the interface between two insulating oxides, LaAlO3 and SrTiO3, can be switched between insulating and conducting states using an applied voltage [Thiel et al., Science (2006) 313, 1942].

The researchers from the University of Augsburg, Germany have now teamed up with scientists at the University of Pittsburgh and the Naval Research Laboratory to show that a biased AFM tip can control this metal-insulator transition locally. A positive bias produces a metallic state at the interface in the region below the tip, while a negative bias creates an insulating state.

“We were able to reversibly write and erase lines as small as 3 nm and make isolated conducting dots that were smaller still,” says lead author Jeremy Levy of the University of Pittsburgh. “There are a number of possible future applications in the field of storage and computing, and we are interested in exploring them now.”

Jonathan Wood