cfaed Seminar Series
cfaed Seminar Series
Prof. Ulrich Schwarz , TU Chemnitz
Polarization in InGaN Quantum Wells
07.07.2016 (Thursday) Seminar Room 115 (HAL) , Hallwachsstr. 3 , 01162 Dresden
Light emitting diodes (LEDs) ranging from high-power, high efficiency
ones for solid-state lighting to tiny micro-LEDs used for stimulation of
nerve cells in the field of optogenetics as well as laser diodes in the
violet-blue-green part of the light spectrum have one thing in common:
they are based on spontaneous electroluminescence and stimulated
light emission in quantum wells made from the semiconductor Indium-
Gallium-Nitride (InGaN). Due to their crystal symmetry, all group-IIInitrides
(AlN, InN, GaN) and their compounds are ferroelectric,
piezoelectric, and optical birefringent. I will discuss these effects and
their impact on the physical properties of the above mentioned devices.
Ulrich T. Schwarz received the Ph.D. degree in physical science and the Habilitation
in physics from the University of Regensburg, Germany, in 1997 and 2004,
respectively. In 2004, he joined the faculty of the University of Regensburg as an
Assistant Professor. In 2009 he was appointed Professor (W2) at Freiburg University
and the Fraunhofer Institute for Applied Solid State Physics (IAF) in Freiburg,
Germany. After a short stay in industry at Osram OS, department of analytics and
metrology, he accepted a full professor position at TU Chemnitz, in October 2015.
His research focus is on semiconductor optoelectronics of group-III-nitrides. He is
specialized in spectroscopy with high temporal, spatial, and spectral resolution.
Topics include quantum efficiency, band structure, polarized emission, degradation
mechanisms, and dynamics in LEDs and laser diodes.
He received a Feodor Lynen scholarship from the Alexander von Humboldt
foundation. From 1997 to 1999, he was a Post-Doctoral Fellow at Cornell University,
Ithaca, NY, where he was engaged in research on intrinsically localized modes. In
2001, he joined the group of Prof. R. Grober at Yale University, New Haven, CT. In
2006/2007, he visited Kyoto University, Kyoto, Japan, with an Invited Fellowship
(long-term) awarded by the Japanese Society for the Promotion of Science (JSPS).
Dr. Schwarz is senior member of the Optical Society of America, and member of SPIE
– the international society for optics and photonics – and of the German Physical