High-power and high-brightness diode lasers serve as pump lasers for modern femtosecond laser systems. In turn, advanced laser-based spectroscopic methods that are invented or improved at MBI are applied to such optoelectronic devices in order to analyze their properties. The objects of investigation are either the high-power and high-brightness diode lasers themselves or parts of such devices such as test samples representing, e.g., novel active region materials or specially treated front facets of the devices. A primary objective is to improve insight into the microscopic nature of the mechanisms defining the limits of semiconductor device operation.

The following topics are presently in the focus of the research:

• thermal device properties and particularly front-facet heating
• defect creation and accumulation within the active region, and
• mechanical stresses

They are quantitatively analyzed in very different device structures provided by our industrial partners, such as OSRAM Opto Semiconductors, THALES RESEARCH AND TECHNOLOGY, JENOPTIK Laserdiode and DILAS GmbH. Main institutional partners are the Ferdinand-Braun-Institute on the local WISTA campus in Adlershof and the Fraunhofer Institutes for Applied Solid-State Physics and Laser Technology.

Taking into account the analytical results of MBI, these partners create novel generations of optoelectronic devices with increased brightness and reliability.

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.

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 follow-up conference DRIP-XIII will be held in the USA.

In 2007 and 2009 the group is involved into the organization of the symposium K "Semiconductor Nanostructures towards Electronic and Optoelectronic Device Applications" I and II, respectively. Details on this full-week symposium are here.

The project group serves as the workpackage coordinator of WP5 "Reliability" in the Integrated European Union project BRIGHTER.EU "World Wide Welfare: high-BRIGHTness semiconductor lasers for gEneric Use" (2006-2009).

We are involved into the work of the national project HEMILAS by a subcontract given by OSRAM Opto Semiconductors (2008-2011). This activity is supported by the Federal Ministry of Education and Research in line with the actual research program "Optical Technologies for the 21st Century".