Semiconductor Optics - RG Callsen

Profile of the RG Callsen

Our research group (RG Callsen) at the Institute of Solid State Physics of the University of Bremen focusses on a joint optical and thermal characterization of semiconductors (Si, Ge, SiC, GaN, AlN, ZnO, Ga₂O₃, etc.) and related nanostructures. Such nanostructures include membranes, quantum wells, nanowires, and quantum dots, which can, e.g., be employed in single and few photon sources, LEDs and semiconductor lasers. The optical material characterization mainly comprises microphotoluminescence spectroscopy (?PL), photoluminescence excitation spectroscopy (PLE), Raman spectroscopy, and ellipsometry. For the thermal analyses we perform one-laser Raman thermometry (1LRT), two-laser Raman thermometry (2LRT), and frequency-domain thermal reflectance (FDTR) measurements. Commonly, most setup of our experimental setups that serve a joint optical and thermal material characterization are fully customized, meaning that we control every single component of our experiments. Based on this research "ansatz" we develop novel spectroscopic systems that provide unique insight into the intricate and strongly interlinked transport physics of excitons, exciton-polaritons, charge carriers, and thermal phonons.