Our research is focused on semiconductor-based optoelectronic devices, such as high-power and high-brightness diode lasers. In terms of power conversion this class of devices represents the most efficient man-made light sources ever assembled. They convert up to three quarters of electric energy into light and reach continuous wave kilowatt output powers from a single semiconductor chip. The power not converted into light, however, causes a strong local heating and device degradation, eventually limiting the device lifetime. Among other damage phenomena, the process of Catastrophic Optical Damage (COD) is studied. COD is a sudden degradation mechanism, taking place at the outcoupling facet of diode lasers. Research in this field also addresses defect creation processes in nanostructure-based devices such as quantum dot lasers. The main goals of our work are getting insight into the physical mechanisms that are setting ultimate limits of modern photonic devices and to develop strategies for the improvement of high-power and high brightness laser sources.
Investigations of transient recombination (ps to ns) and ultrafast transport processes (sub-ps) in optoelectronic materials and epitaxial structures such as quantum-well or quantum-dot structures – in part even device structures – complement these primary device-related analytical activities
There are close scientific links to research institutes such as the Ferdinand-Braun-Institute (Berlin), Max Planck Institute of Microstructure Physics (Halle/S.), the Fraunhofer Institute for Applied Solid-State Physics (Freiburg), and the Ioffe Physical Technical Institute in St. Petersburg (Russia). University partners are the Universidad de Valladolid (Spain), the Institute of Physics of the Technical University of Lódz (Poland), the Cardiff University, (UK), and the St. Petersburg State University (Russia). There are close links to optoelectronic companies such as OSRAM Opto Semiconductors Regensburg, JENOPTIK Laser, and Alcatel-Thales II-V Lab. In addition there is also cooperation with small and medium-sized enterprises on the Adlershof campus. Taking into account the analytical results of MBI, the partners create novel generations of optoelectronic devices with increased brightness and reliability.
In 2007 the group has organized the "12th International Conference on Defects-Recognition, Imaging and Physics in Semiconductors",
DRIP-XII in 2007 in Berlin. The conference DRIP-XIV will be held in September 2011 in Japan.
In 2007, 2009, and 2011 the group is involved into the organization of the symposium G "Semiconductor Nanostructures towards Electronic and Optoelectronic Device Applications" I, II, and III, respectively. Details on this full-week symposium are
In 2010, we successfully completed the work on the integrated project BRIGHTER, funded by the European Commission
(see http://www.ist-brighter.eu/). Within this project we started the work on COD and served as a workpackage leader. Three other external projects contribute to the funding of our research. Within the BMBF projects HEMILAS, SPECTRALAS
(see http://www.ot-inlas.de), and BMWi project "Breitbandige Lichtquelle mit Quantendots dotiertem Glas - Weißlichtquelle" we act as a sub-contractor for OSRAM Opto Semiconductors Regensburg, JENOPTIK Laser, Jena, and Institute for Scientific Instruments, Berlin, respectively.