News

December 4, 2009

Friday, 3:00PM
8 Saint Mary's Street, Rm 210

Cosponsored by ECE and Physics

flyer

Dr. Clemens Heske
Chemistry Department
University of Nevada at Las Vegas

Using Soft x-rays to Look Into Interfaces of Energy Conversion Devices

Abstract:

The electronic and chemical structure of interfaces is of central importance for understanding and tailoring of materials, chemical processes, and electronic devices. Thus, over the past few decades, significant experimental (and theoretical) insights into electronic and chemical structures of well-defined model surfaces have been gained by a variety of approaches, and properties of interfaces have been inferred.

But what if the interface (e.g., a contact to a semiconductor device), is not only buried, but also non-ideal? What if intermixing processes take place, impurities are localized, preferential bonding exists, etc.?

The purpose of this talk is to demonstrate how a tool chest of soft x-ray spectroscopies (including lab-based techniques and approaches using high-brilliance synchrotron radiation) is uniquely suited to address such questions. In the talk, I will discuss a variety of applications for compound semiconductors (light-emitting devices, thin film solar cells, and devices for photoelectrochemical water splitting), and it will be shown how soft x-rays can be utilized to shed light on the electronic and chemical properties of the surfaces and interfaces involved.

Biography:

Clemens Heske received his Ph.D. (Dr. rer. nat.) in Physics from the University of Würzburg in Germany in 1998. After two years as a postdoctoral fellow at the Lawrence Berkeley National Laboratory, he became a “wissenschaftlicher Assistent” at the University of Würzburg and completed his German Habilitation in Experimental Physics in December of 2003.  In 2004, he joined the UNLV Chemistry Department as an Associate Professor for Materials Chemistry and was tenured (promoted to Professor) in the summer of 2007 (2009). Dr. Heske uses soft x-rays to study surfaces and interfaces in a wide variety of materials system for energy conversion. With the expertise and technical skills of his group, he teams up with over thirty different national and international partners in academia, national labs, and industry to investigate and improve thin film solar cells, materials for hydrogen production, storage, and consumption, light-emitting devices, nuclear fuel, and other systems that involve interfaces and require a deeper understanding of their properties.