Research
Dr. Bernstein is engaged in a wide variety of research projects as described below.
Quilt Packaging
Bernstein is co-inventor (with Patrick Fay, Wolfgang Porod, and Qing Liu) of a chip-to-chip interconnect method called “Quilt Packaging,” in which small metal nodules protruding from the edges of chips allow them to communicate with ultrawide bandwidth and low power. This ongoing work has led to world record interconnect bandwidth, with less than 1 dB of insertion loss as demonstrated up to 220 GHz. Bernstein is co-founder of Indiana Integrated Circuits, LLC, a Notre Dame spin-off company whose mission is to commercialize this exciting new technology. See www.indianaic.com.
Infrared Nanoantennas and Nanothermocouples
Along with Wolfgang Porod, Alexei Orlov, Edward Kinzel, and Gergo Szakmany, I am involved in the design, fabrication, and characterization of nanoantennas for infrared imaging. In this project, nanoscale antennas are tuned to mid- and long-wave infrared wavelengths and are fabricated with integrated nanothermocouples. These nanoantennas resonate with incoming infrared light and capture the radiation. The resulting antenna current heats a nanofabricated thermocouple, which converts the IR light into electrical signals through the Seebeck effect. We call these devices thermoelectrically coupled nanoantennas, or TECNAs for short. TECNAs come in two varieties: half-wave dipole antennas and log-spiral antennas. These different geometries offer selectivity for linear, circular, and elliptical polarizations of the incoming IR light. The physical size of each nanoantenna sets its wavelength sensitivity, enabling multi-color imaging as the technology matures. TECNAs are fabricated above a quasi-hemispherical cavity that thermally isolates them from the substrate. This cavity also provides directional selectivity and beam-steering capabilities, similar to a traditional RF dish antenna. Significant progress has already been made in this area, and development is ongoing.
Nanomagnet Logic
Bernstein directed the fabrication and materials related aspects of Nanomagnet Logic (NML) (along with Porod, Michael Niemier and Sharon Hu), which is a variation of the quantum-dot cellular automata (QCA) approach, as applied to nanomagnets. One advantage of nanomagnets is that they are well-behaved at room temperature, and it is straightforward to demonstrate NML operation of logic gates and more-complicated arrangements.
Nanopatterning with DNA Origami
In collaboration with Marya Lieberman from the Department of Chemistry and Biochemistry, Bernstein explored the self-assembly of DNA origami to use in nanopatterning. The DNA origami are synthesized in Lieberman’s group, and Bernstein’s group is responsible for creating nanopatterns on smooth surfaces to which the origami self-assemble and organize. The goal of this project is to develop directed self-assembly of complex electronic arrangements for computing.