Optical Tweezers Assemble Materials At The Nanoscale

Researchers have developed a method to make reproducible nanoscale manufacturing possible. The team adapted a light-based technology employed widely in biology — known as optical traps or optical tweezers — to operate in a water-free liquid environment of carbon-rich organic solvents, enabling new potential applications.

The optical tweezers act as a light-based “tractor beam” that can assemble nanoscale semiconductor materials precisely into larger structures. Unlike the tractor beams of science fiction, which grab spaceships, the team employs optical tweezers to trap materials that are nearly one billion times shorter than a meter.

The scientists then grabbed one of the germanium nanorods using the light-based “tractor beam.” The beam’s energy superheats the nanorod, melting the bismuth cover. They then direct a second nanorod into the “tractor beam” and connect them end to end due to the molten bismuth cap at the end. The repetitive procedure allowed the scientists to create patterned nanowire heterostructures with repetitive semiconductor-metal junctions five to ten times longer than the parts.

It is a new approach to nanoscale manufacturing. No chamber surfaces are involved in manufacturing, which minimizes strain formation or other defects. All components are suspended in solution, and we can control the size and shape of the nanostructure as it is assembled piece by piece.

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