FOR 506:  Physics of nitride-based, nanostructured, light-emitting devices

• Subject Area: Physics
• Term: from 2003 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5470211

The goal is to develop novel nanostructured devices based on group-III nitrides involving-- InGaN/GaN quantum dot laser-- surface emitting lasers (VCSEL)for the blue spectral region.The underlying physical processes connected with the realisation of self-organised and/or nanostructured devices will be studied in a cooperation between the groups of the epitaxial growth, the surface physics, the structural characterisation and the optical spectroscopy. A strong interaction with theoretical groups has been established. It involves multiscale growth and doping simulations, the electronic properties of quantum dots and the microscopic theory of nanostructured laser devices.In terms of current international efforts, the whole team aims at ambitious goals in the field of device-oriented basic research of nitride-based optoelectronics. The intended device structures have not been realised up to now and are subjects of research world wide. Concerning a blue emitting quantum dot laser diode basic studies of the self-organised growth of InGaN dots are performed at the moment using molecular beam epitaxy (MBE) as well as metal organic vapour phase epitaxy (MOVPE) as growth methods. Especially the mechanism of dot formation and the physical processes during the overgrowth need to be clarified. For that micro-photoluminescence studies of localisation centres are important. In parallel, the theoretical modelling of the quantum dot properties are performed in close interaction with the experimental findings.For a monolithic vertical cavity surface emitting laser (VCSEL) high reflectivity DBR-mirrors (distributed Bragg-reflectors) are the most crucial point. A novel approach using GaN and a superlattice of AlN/GaN has been successfully developed resulting in a reflectivity of 89% at the moment. Here the growth activities are accompanied by growth simulations and structural studies using transmission electron microscopy.

• DFG Programme: Research Units

Projects

• Calculation of the electronic energy eigenvalues and eigenstates and Coulomb and dipole matrix elements for realistically modelled quantum dots (Applicant Czycholl, Gerd )
• Defects, chemistry and ordering in nitride nanostructures (Applicant Rosenauer, Andreas )
• Growth and characterization of short-wavelength surface emitting lasers based on GaN (Applicant Hommel, Detlef )
• Growth modes and interfaces of InGaN nanostructures by planar and cross-sectional STM (Applicant Falta, Jens )
• Microscopic theory of nanostructured laser devices with short-wavelength emission (Applicant Jahnke, Frank )
• Multiscale growth and doping simulations of nanostructured devices (Applicant Neugebauer, Jörg )
• Nanostructuring of homo- and heteroepitaxial light emitters for enhanced quantum efficiency using photonic crystal components (Applicant Figge, Stephan )
• Nitride-based, nanostructured, light-emitting devices (Applicant Hommel, Detlef )

• Spokesperson: Professor Dr. Detlef Hommel
• Deputy: Professor Dr. Frank Jahnke