Events Calendar

Seminar by Jongseung Yoon

Speaker: Jongseung Yoon, USC, Assistant Professor in Chemical Engineering and Materials Science

Talk Title: Inorganic Semiconductor Micro/Nanomaterials and Deterministic Assembly by Transfer Printing for Unusual Format Photovoltaics

Abstract: Solar modules that involve large collections of small, ultrathin photovoltaic cells integrated on a thin sheet of plastic offer attractive features that can not be achieved with conventional approaches. In the first part of my talk, I will describe the use of ultrathin, monocrystalline silicon solar microcells generated from the bulk wafer through wet chemical etching and top-down lithographic processes as building blocks for creating unconventional photovoltaic modules enabled with massively parallel printing techniques. The resulting devices can provide many useful characteristics, including high degrees of mechanical flexibility, user-definable levels of transparency, ultra-thin form factor micro-optic concentrator designs, together with the potential for low cost and high efficiency. In the second part, I will discuss releasable epitaxial multilayer assemblies of gallium arsenide (GaAs) based compound semiconductors for their use in high performance photovoltaics. While compound semiconductors such as GaAs provide unmatched performance in photovoltaic and optoelectronic devices, current methods for growing and fabricating these materials are incompatible with the most important modes of use, particularly in photovoltaics, where large quantities of material must be distributed over large areas on low cost, amorphous foreign substrates. We developed new methods that address many of these challenges, through cost effective production of high quality functional films of GaAs from thick, epitaxial assemblies formed in a single deposition sequence on a growth wafer. Specialized designs enabled separation, release and assembly of individual active layers in these stacks to create devices on various substrates, in quantities and over areas that exceed possibilities with conventional approaches.



Biography: Prof. Yoon received his B.S. degree from Seoul National University in South Korea, and Ph.D. degree in Materials Science and Engineering from the Massachusetts Institute of Technology in 2006. Prof. Yoon has been a Beckman Institute Postdoctoral Fellow at the University of Illinois at Urbana-Champaign since 2007. At UIUC, Prof. Yoon has worked on developing new approaches for high performance, unusual format photovoltaic and optoelectronic systems based on arrays of monocrystalline Si and GaAs and micro-transfer-printing techniques. Prof. Yoon’s research interests at USC lie in exploiting various classes of micro/nanomaterials and heterogeneously integrating them into functional devices in the manner that their electrical, optical, mechanical, and thermal properties are optimally combined together for advanced applications in energy-harvesting, photonics, electronics, as well as sensor technologies.

Host: EE-Electrophysics

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248

Audiences: Everyone Is Invited

Contact: Marilyn Poplawski