3D nanostructures "done in your garage"
8 Dec 2014
Researchers at North Carolina State University (NCSU) have developed a low-cost lithography technique that uses nanoscale spheres to create 3D structures.
The technique is said to be “significantly less expensive” than current methods, and could potentially lead to the development of low-cost biomedical, electronic and photonic instrumentation.
“Our approach reduces the cost of nanolithography to the point where it could be done in your garage,” said Chih-Hao Chang, an assistant professor of mechanical and aerospace engineering at NCSU.
“We are using the nanosphere to shape the pattern of light, which gives us the ability to shape the resulting nanostructure
Lead author Chih-Hao Chang
Unlike more conventional methods which rely on stacking two-dimensional patterns to create 3D structures, the NCSU approach placed nanoscale polystyrene spheres on the surface of a photosensitive film.
The nanospheres are transparent, but bend and scatter the light that passes through them in predictable ways according to the angle that the light takes when it hits the nanosphere, the researchers said.
According to the researchers, the nanolithography was controlled by altering the size of the nanosphere, the duration of light exposures, and the angle, wavelength and polarisation of light.
“We are using the nanosphere to shape the pattern of light, which gives us the ability to shape the resulting nanostructure in three dimensions without using the expensive equipment required by conventional techniques,” Chang said.
“And it allows us to create 3D structures all at once, without having to make layer after layer of 2D patterns.”
Specifically, this technique could be used to develop an array of nanoneedles for use in drug delivery, or to create nanoscale ’inkjet printers’ for printing electronics or biological cells, the researchers said.
Looking ahead, the researchers will attempt to manipulate their technique to better control the shape of resulting structures.
“We’re exploring the use of nanosphere materials other than polystyrene, as well as nanoparticle shapes other than spheres,” Chang said.
“And ultimately we want to look at ways of controlling the placement of particles on the photosensitive film in patterns other than uniform arrays.”
A full account of the study has been published in the journal Small.
