Doping technique brings nanomechanical devices into the semicondu...( MADISON - With the help of a device ...)

MADISON - With the help of a device capable of depositing metals an atom at a time in the materials used in computer chips, a team of University of Wisconsin-Madison engineers has successfully blended modern semiconductor technology and nanomachines.

The work, reported this week (Sept. 26) in the journal Physica Status Solidi, marks the advent of a new class of nanomechanical devices with implications ranging from improved solar energy cells and light-emitting diodes to highly sensitive probes capable of measuring single biological molecules.

"This is a marriage of two different fields," explains Robert Blick, a UW-Madison professor of electrical and computer engineering. The ability to confer the properties of a semiconductor onto the submicroscopic machines scientists are now learning how to build opens the door to a host of new tiny mechanical devices that can be manipulated with a single electron or, in the case of a biological application, a single molecule such as a protein.

The new work was conducted using a unique device known as a focused ion beam writer, an instrument that, in essence, operates like a sandblaster and can shower a sample of silicon with atoms to impregnate the material with metal in precise patterns at the nanoscale.

In the new study, Blick's group, including lead author of the paper Dominik V. Scheible, was able to deposit a small plume of gallium atoms into a silicon nanomachine and confer electromechanical properties - the ability to drive moving parts with electrons.

"This constitutes a direct combination of mechanical and electric tunability with unprecedented precision," the authors write in the new report. "This will considerably enhance the mechanical properties of (nanomachines)."

At present, nanomechanical devices are sculpted from sandwiches of silicon and metal. The new technique means the metal layer can be removed completely, making the nano devices lighter, more sen
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