Wednesday, September 28
ECE & MSE, University of Utah
Processing and Characterization of CdTe Thin Film Photovoltaics
In the past decade, CdTe has become the leading thin film photovoltaic material, becoming the first PV technology to break the $1/Watt manufacturing cost barrier (now estimated at $0.54/Watt). It is still breaking efficiency records for thin film photovoltaics, now on its way to 21.5%, and recently reaching 10 GW total installed capacity. However, current best estimates for PV electricity reaching widespread, unsubsidized grid parity require an additional halving of the cost per Watt. My group has been working to apply high powered lasers in thin film CdTe manufacturing in annealing and surface treatment applications. In this talk, I will first give an overview of our lab’s capabilities and some specific results from CdTe, and then review our progress in recrystallizing and treating CdTe thin films, in developing in-situ monitoring during CdCl2 treatments, and in modifying the back contact. Based on our work on laser-driven back-contact preparation, we have begun investigating the connections between back-contact processing, 2D composition, and device performance. Lastly, I will discuss some fascinating avenues for future work in which light has non-trivial effects on point defects that might find application in CdTe processing.
Mike Scarpulla is an Associate Professor in the departments of Materials Science & Engineering and Electrical & Computer Engineering at the University of Utah, and is an Editor for the IEEE Journal of Photovoltaics. Following an Sc.B. from Brown University and a PhD from UC Berkeley, he did post-doctoral research at UC Santa Barbara, and joined the faculty at the University of Utah in 2008. His current research focus is laser processing and the advanced characterization of compound semiconductors, primarily for use as thin film photovoltaics.
Wednesday, October 5
Duke University, Electrical & Computer Engineering
Scaling, Printing, and Sensing: A New Era for Electronics Made Possible Using Nanomaterials
Silicon-based electronics remain the backbone of the ongoing digital revolution and continue to enhance the computational ability and accessibility of data. As the range of possible applications for electronics grows, so does the realization that there are distinct limits to what silicon can do. Meanwhile, nanomaterials have been studied for decades for their attractive electronic properties coupled with mechanical flexibility, thermal resilience, and compatibility with solution-phase processing. From 1D carbon nanotubes (CNTs) to 2D graphene and transition metal dichalcogenides (TMDs), there is a growing list of nanomaterial options. In this talk, the promises that nanomaterials offer in three distinct application areas—1) scalable low-voltage transistors, 2) printed electronic systems, and 3) ultrasensitive biological sensing—will be discussed, including experimental evidence for each. These applications draw from capabilities that are unique to nanomaterials, which leads to performance, fabrication, and/or function that are not possible with traditional semiconductors. For instance, the low-cost printing of electronic circuits and sensors that must operate within the harsh environment of an automobile tire, providing data that enhances safety and function, will be demonstrated. Low-voltage negative capacitance transistors from 2D TMDs that can prove transformative for future computing will also be discussed. Finally, fully printed bioelectrical immunoassays will be shown that offer a path for revolutionizing point-of-care diagnostic healthcare. As the coverage of this talk will be relatively broad in terms of applications, the primary takeaway will be an overview of a new era of electronics that is uniquely possible using nanomaterials.
Prof. Aaron Franklin received his PhD in Electrical Engineering from
Purdue University, followed by six years as a research scientist at the
IBM Watson Research Center in Yorktown Heights. At Duke University, he
leads the Laboratory of Electronics from Nanomaterials, which has three
primary research thrusts: 1) nanomaterials in high-performance
nanoelectronic devices, 2) nanomaterial inks for low-cost printed
electronics, and 3) harnessing nanomaterial sensitivity in bioelectrical
Wednesday, November 9
Chemistry & Physics, Florida Gulf Coast University
Introduction to Gamma-ray Astrophysics
Observational Gamma-ray Astrophysics was born in the 1960s. NASA's Compton GammaRay Observatory (CGRO) was launched by Space Shuttle Atlantis in 1991 and revealed many mysterious high energy phenomena in the Universe such as Gamma-ray Bursts (GRBs), 511 keV emission from the galactic center, Gamma-ray Pulsars, so on. Currently, NASA's Fermi Gamma-ray Space Telescope & SWIFT, and ESA's INTErnational Gamma-RAy Laboratory (INTEGRAL) are still operational in these fields. We will discuss highlights from the past and current missions as well as the future of Gamma-ray Astrophysics.
Dr. Ken Watanabe received his BS in Physics from TOHOKU University in Japan, and PhD from CLEMSON University. He is currently Physics Program Leader in Department of Chemistry and Physics at Florida Gulf Coast University. His research expertise is Gamma-ray Astrophysics. Before joining FGCU he worked at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD as Astrophysicist. The space missions he worked on at GSFC were Compton Gamma-Ray Observatory (CGRO), Rossi X-ray Timing Explorer (RXTE), and INTErnational Gamma-RAy Laboratory (INTEGRAL) which is a space mission of the European Space Agency (ESA), as well as Earth Observing missions. His main research interests are Cosmic Diffuse Gamma-ray Background, Nucleosynthesis in the Universe, 511 keV line at the galactic center, Gamma-ray transient sources, Gamma-Ray Bursts (GRBs) after glow, and Terrestrial Gamma-ray Flashes (TGFs). His collaborators and he constructed an optical observation system on the FGCU campus to study connections between Sprites and TGFs by utilizing the optical data with additional data from NASA’s Fermi and RHESSI missions.
We welcome anyone who wish to attend, and typically serve refreshments
ten minutes before the colloquium begins. Speakers generally keep
their presentation accessible to undergraduate physics students.