Nano machine shop shapes nanowires, ultrathin films
A new "nano machine shop" that shapes nanowires and ultrathin films could represent a future manufacturing method for tiny structures with potentially revolutionary properties.
The structures might be tuned for applications ranging from high-speed electronics to solar cells, and also may have greater strength and unusual traits such as ultrahigh magnetism and "plasmonic resonance," which could lead to improved optics, computers, and electronics.
The researchers used their technique to stamp nano- and microgears; form tiny circular shapes out of a graphene; and change the shape of silver nanowires, says Gary Cheng, an associate professor of industrial engineering at Purdue University.
"We do this shaping at room temperature and atmospheric pressure, like a nano machine shop," says Cheng, who is working with doctoral students Ji Li, Yiliang Liao, Ting-Fung Chung, and Sergey Suslov and physics professor Yong P. Chen.
Graphene and nanowires have numerous potential applications. However, technologies are needed to tailor them for specific uses. The new method, called laser shock-induced shaping, makes it possible to tune nanowires by altering electrical and optoelectrical properties that are critical for electronic components.
The researchers also have shown how laser shock-induced shaping can be used to change the properties of graphene, a step toward harnessing the material for electronic applications.
Findings were detailed in research papers published in Nano Letters, and the work also was highlighted in Nature Photonics.
The technique works by using a multilayered sandwich structure that has a tiny mold at the bottom. Nanowires were situated directly above the mold, and other materials were layered between the nanowires and a glass cover sheet. Exposing this layered "forming unit" to an ultrafast 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 says. "The laser shock-induced shaping approach is fast and low-cost."
Source: Purdue University