'Nano machine shop' shapes nanowires, graphene

The team at Purdue University used a technique called laser shock induced shaping to stamp nano and microgears, form tiny circular shapes from graphene and change the shape of silver nanowires. "We do this shaping at room temperature and atmospheric pressure, like a nano machine shop," said Gary Cheng, an associate professor of industrial engineering at Purdue. The researchers say that their method can tune nanowires by altering electrical and optoelectrical properties that are critical for electronic components, as well as change the properties of graphene, which is a step towards harnessing the material for electronic applications. The technique works by using a multilayered sandwich structure with a tiny mold at the bottom. Nanowires are situated directly above the mold, and other materials are layered between the nanowires and a glass cover sheet. Exposing this layered 'forming unit' to an ultra fast pulsing laser causes one of the layers to burn up, generating a downward pressure that forces the nanowires into the mold and changes their shape. "The process could be scaled up for an industrial roll to roll manufacturing process by changing laser beam size and scanning speed," Cheng said. "The laser shock induced shaping approach is fast and low cost."