University of Illinois at Urbana-Champaign
A materials scientist comments on two methods for three-dimensional nanofabrication.
Methods for nanofabrication are crucially important to research in all areas of nanoscience and nanotechnology because they allow for the creation of functional structures — a key step towards useful applications and devices. Many techniques are available, but all have significant shortcomings and few are compatible with true, high-volume manufacturing modes. As the director of a centre for nanomanufacturing funded by the US National Science Foundation, I am deeply interested in emerging developments in this area.
Two papers on nanofabrication caught my attention. Both use sharp, scanning tips to form three-dimensional (3D) nanostructures. This 3D capability is important because it is unavailable in established techniques such as those used in the semiconductor industry.
In one paper, Jie Hu and Min-Feng Yu at the University of Illinois at Urbana-Champaign use nanometre-scale glass nozzles with engineered shapes to electroplate metal onto solid surfaces (J. Hu and M.F. Yu Science 329, 313–316; 2010). The positions of the nozzle and substrate are precisely controlled, enabling directed ‘writing’ of nanometre-scale conducting wires in freely suspended 3D arrangements.
In the second paper, Armin Knoll at IBM Research in Zurich and his colleagues use sharp tips as sources of heat to locally strip material from thin films of molecular glasses and thereby sculpt 3D shapes with nanometre-scale accuracy (D. Pires et al. Science 328, 732–735; 2010). The authors fabricate diverse structures, including a 25-nanometre-high replica of the Matterhorn, one of the Alps’ highest peaks.
Both techniques offer valuable capabilities in nanofabrication that seem to be scalable for practical use. Successful outcomes of efforts such as these will have central roles in the translation of new knowledge in nanoscience into meaningful forms of nanotechnology.