EE Special Seminar
Ultra-flat and Ultra-small: New Approaches to Nanofabrication for Plasmonics and Biosensing
I will present our recent work based on two unconventional nanofabrication techniques, namely, template stripping for making ultra-smooth patterned metals and atomic layer lithography for mass-producing sub-10 nm gaps.
With template stripping, instead of directly patterning noble metal films, which are difficult to plasma-etch, we engineer inverse patterns in crystalline silicon templates using mature IC processing techniques. After metal deposition and peeling, ultra-smooth patterns in the silicon template are faithfully replicated onto a deposited metal film. We have used template stripping to create high-performance plasmonic gratings, waveguides, coaxial aperture resonators, nanohole arrays, and ultra-sharp pyramidal tips for various sensing and spectroscopy applications.
Recently our group has demonstrated a new technique called atomic layer lithography, which enables wafer-scale production of ultra-long (up to centimeters) and single-nanometer gaps in various metals. This technique converts Angstrom-scale thickness resolution of atomic layer deposition (ALD) into ultra-high patterning resolution, and can be practiced using only standard photolithography, ALD coating, and a planarization step that is as simple as Scotch tape peeling. While the method is very simple, the resulting ultra-long nanogaps have been used for a wide range of applications, including extraordinary optical transmission through single-nanometer slits, super-coupling of light into coaxial apertures, nonlinear optics, ultralow-power electronic trapping of quantum dots, and surface-enhanced infrared spectroscopies, to name a few. I will present broader potential applications of this enabling technology.
Sang-Hyun Oh obtained his B.S. in Physics from KAIST, Korea, and Ph.D. in Applied Physics from Stanford University (advisor: Jim Plummer). After postdoctoral research at Bell Laboratories, Murray Hill, and at the University of California at Santa Barbara, he joined the ECE department at the University of Minnesota, Twin Cities in 2006. He currently holds the Sanford P. Bordeau Chair in Electrical Engineering and directs a lab focused on nanofabrication, biosensing, and nano-optics. He is a recipient of faculty awards from the ONR, DARPA, NSF, ACS, and 3M. He was a visiting professor at Imperial College London and ETH Zurich. Group: http://nanobio.umn.edu
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