DFG Research Unit 2857

Copper Iodide as Multifunctional Semiconductor

P06: Optical Properties of CuI, Doped CuI and CuI-Based Alloys

Dr. Chris Sturm

The aim of the project is a detailed investigation of the optical properties of copper halides and copper halides-based alloys. Of special interest are the impact of the halide composition on the optical properties, such as the dielectric function and the properties of the underlying optical transitions, as well as the emission and phonon properties. For this purpose, binary compounds as well as ternary and quaternary alloys will be investigated by means of a variety of optical methods, e.g., (spatially-resolved) spectroscopic ellipsometry, (micro) reflectivity, Raman spectroscopy, time- and spatially-resolved photoluminescence spectroscopy and excitation spectroscopy. Due to the large exciton oscillator strength in this material system, a strong light-matter interaction takes place. Thus, instead of the typically used picture of a recombination of excitons, exciton-polaritons have to be used for the interpretation of the optical spectra. The impact of the alloy composition on the exciton oscillator strength and thus on the exciton-polariton dispersion as well as the related inter- and intrabranch scattering processes in bulk crystals will be investigated, which allows a deeper insight into the exciton-polariton physics in bulk crystals in general.