Direct Imprinting of Porous Substrates: A Rapid and Low-Cost Approach for Patterning Porous Nanomaterials
Judson D. Ryckman†, Marco Liscidini‡, J. E. Sipe§, and S. M. Weiss†
†Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, USA
‡Dipartimento di Fisica “A. Volta”, Universita degli Studi di Pavia, via Bassi 6, 27100 Pavia, Italy
§Department of Physics and Institute for Optical Sciences, University of Toronto, 60 St. George St. Toronto M5S 1A7 Ontario, Canada
A new technique has been developed, and is reported in this paper, for one-step, direct patterning of porous nanomaterials, including insulators, semiconductors, and metals without the need for intermediate polymer processing or dry etching steps. The process, which is called “direct imprinting of porous substrates,” utilizes reusable stamps with micro- and nanoscale features that are applied directly to a porous material to selectively compress or crush the porous network. The stamp pattern is transferred to the porous material with high fidelity, vertical resolution below 5 nm, and lateral resolution below 100 nm. The process is performed in less than one minute at room temperature and at standard atmospheric pressure. Structures ranging from subwavelength optical components to microparticles have been demonstrated and present exciting avenues for applications including surface-enhanced Raman spectroscopy (SERS), label-free biosensors, drug delivery, solar energy conversion, and battery anodes.
This new approach, direct imprinting of porous substrates, offers an exciting, cost-effective, rapid, and straightforward methodology for realizing a large variety of important structures based on a wide class of porous nanomaterials.
This user research was supported in part by the Army Research Office Grant W911NF-09-1-0101. SEM and AFM were performed at the Vanderbilt Institute of Nanoscale Science and Engineering. Photolithography, electron-beam-lithography, and reactive ion etching of the silicon stamps were performed at the Center for Nanophase Materials at Oak Ridge National Laboratory, which is supported by the Office of Basic Energy Sciences, U.S. Department of Energy. The research was published as Ryckman et al., “Direct Imprinting of Porous Substrates: A Rapid and Low-Cost Approach for Patterning Porous Nanomaterials,” Nano Lett. 2011, 11, 1857–1862, dx.doi.org/10.1021/nl1028073, and featured on the cover of the issue.