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Colloquium | Materials Science Colloquium | Materials Science Division

Non-Planar and Mixed-Dimensional Heterostructures for Conventional and Unconventional Computing

Materials Science Colloquium

Abstract: With the advent of artificial intelligence, silicon-based computing continues to be as transformational in the 21st Century as it was in the 20th. However, 20th Century approaches to information processing, communication, and storage have led to well-known bottlenecks that can be overcome only by expanding the basis set of materials for computing. Furthermore, even greater opportunities await by using materials to compute in new ways.

We are interested in discovering how low-dimensional materials beyond silicon may advance both conventional and unconventional information processing and communication. We first consider III-V core-shell nanowire heterostructures as compact light sources to accelerate conventional computing by integration on silicon. We then explore how unconventional substrates drive the evolution of branched III-V nanowires to support quantum computing schemes.

In this highly collaborative research, our group focuses on the three-dimensional visualization of nanoscale structure and composition both to visualize the confinement potentials of charge carriers and photons and to identify the fundamental driving forces that control the evolution of the growth interface. Atom probe tomography and synchrotron-based X-ray diffraction are the foundation of our approach to total tomography” of nanoscale heterostructures.

Herbert Kroemer’s famous statement that “…the interface is the device” remains a useful guide to understanding the potential for engineering new functionality at the time of synthesis and highlights an important challenge for nanoscale characterization. In this context, we will also consider the opportunities and challenges presented by two-dimensionalor van der Waals materials, in which the material is also an interface. The challenge of defining new ultra-scaled heterojunctions of mixed dimensionality by direct synthesis is of particular interest to our group.

Bio: Lincoln Lauhon is a professor and associate chair in the department of materials science and engineering at Northwestern University and co-director of the applied physics program. He received a Ph.D. in physics from Cornell and a B.S. in physics from the University of Michigan. At Northwestern, the Lauhon group investigates novel structure-property relationships in nanostructured materials and heterostructures by using correlated imaging methods that probe structure, composition, and function.