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APMS Colloquium

Thursday, March 20, 9:45-10:45 am

Dr. Edward Yu
University of Texas at Austin

Semiconductors for Quantum and Sustainable Energy Applications

Abstract: Semiconductor materials are foundational to technologies ranging from computing to communications to renewable energy. In nearly all cases, control over structure and electronic properties at or near the nanometer scale is essential. However, the dimensions over which such control must be exercised can vary dramatically – from nanometers to meters or larger. We will discuss a variety of recent projects in our laboratory in which semiconductor material and device properties must be controlled or characterized at or near nanometer length scales, but for which the relevant scale for useful application ranges from microns to meters or larger. First, we discuss studies of monolayer transition metal dichalcogenide semiconductors, in which single photon emission can be observed in the presence of tensile strain. We show how proximal probe measurements with a back-gated sample geometry allow the full strain tensor of monolayer transition metal dichalcogenide semiconductors to be measured with spatial resolution of tens of nanometers [1]. These studies provide insight into actual nanoscale strain configurations in geometries for which single photon emission is typically observed, and also enable characterization of phenomena such as piezoelectricity at the nanoscale. We then discuss studies in which strain can be controlled dynamically via electrostatically induced deflection of monolayer WSe2 membranes, an approach with the potential to enable electrical control over single photon emission. In the second part of the presentation, we discuss a variety of approaches for exploiting concepts and processes from the realm of semiconductor manufacturing and device physics – band structure engineering, resistive switching, and nanoscale thin-film reactions – to fabricate photoelectrodes for solar-powered splitting of water molecules into hydrogen and oxygen [2-4]. Our recent results in this area suggest an approach for creation of photoelectrodes for green hydrogen production with scalability and costs similar to those for silicon photovoltaics, thereby offering intriguing prospects for cost-effective green hydrogen production, i.e., production of hydrogen without carbon dioxide emissions.[5] Such advances could help mitigate the over 900 million tons of carbon dioxide generated annually by current methods of commercial hydrogen production that serve a global market for hydrogen of over $170 billion annually.
[1] Nano Lett. 3c03100 (2024).
[2] Nature Nanotechnol. 10, 84 (2015).
[3] Nature Mater. 16, 127 (2017).
[4] Nature Commun. 12, 3982 (2021).
[5] ACS Appl. Energy Mater. 4c00016 (2024).

Edward Yu is Professor of Electrical & Computer Engineering and holds the Judson S. Swearingen Regents Chair in Engineering at the University of Texas at Austin. He received his A.B. (summa cum laude) and A.M. degrees in Physics from Harvard University in 1986, and his Ph.D. degree in Applied Physics from the California Institute of Technology in 1991. He was a postdoctoral fellow at the IBM Thomas J. Watson Research Center from 1991 until 1992, and a faculty member at the University of California, San Diego from 1992 until 2009, when he assumed his current position at the University of Texas. Professor Yu has been the recipient of an NSF CAREER Award, ONR Young Investigator Award, Alfred P. Sloan Research Fellowship, UCSD ECE Graduate Teaching Award, and UT Austin Lepley Memorial Teaching Award, and is an AVS and IEEE Fellow. He has served as a member and chair of the DARPA Defense Sciences Research Council (DSRC), and currently serves at UT Austin as founding Director of the Center for Dynamics and Control of Materials: an NSF MRSEC. Current research interests in his laboratory include photovoltaics and other technologies for energy harvesting and generation; nanoscale imaging and characterization techniques; and solid-state nanoscience and nanotechnology generally. The results of his research have been reported in over 220 archival journal publications and over 300 conference and seminar presentations.

Liberal Arts Building (18), Room 201
Join Via Zoom: https://tinyurl.com/ColloqAPMSMIRA

Sponsored by:

• Center for Materials Interfaces in Research and Applications (¡MIRA!)
• Nanotechnology Collaborative Infrastructure Southwest (NCI-SW) and Arizona State University (ASU)

For more information please contact APMS at APMS@nau.edu