Optical Properties of Group III Nitride Semiconductors

Axel Hoffmann

Institut für Festkörperphysik, Technische Universität Berlin, Germany

Heterostructures of compound group-III nitride-semiconductors are of crucial importance for the rapidly increasing market of optoelectronical devices in the blue and green spectral range. A comprehensive study of the physics of excitons and phonons in group III nitrides using spatially- and time-resolved photoluminescence and micro Raman spectroscopy is shown. We investigated the dynamical behavior of the exciton-phonon interaction in GaN. Furthermore, the optical properties of tenary and quaternary group III nitide quantum wells and quantum dots is presented. Time-integrated and time-resolved photoluminescence investigations demonstrate that localization effects at potential fluctuations play an important role in understanding the exciton dynamics. The results are supported by temperature-dependent photoluminescence and photoluminescence excitation investigations. These results will provide new physical insights since growth conditions are not at thermodynamic equilibrium and therefore one expects different properties, e.g. considering effects like phase separation and fluctuations of the indium, nitrogen or aluminium content.