Natural Sciences, Physical Sciences, Condensed Matter Physics (including Material Physics, Nano Physics), Naturvetenskap, Fysik, Den kondenserade materiens fysik (Här ingår: Materialfysik, nanofysik)

The pursuit of high charge carrier mobility in nanostructures is crucial for advancing both device development and exploring fundamental physics. This study focuses on minimizing scattering to achieve high mobility, employing a polytype type-II interface formed between wurtzite and zincblende InP. On the zincblende side, electrons accumulate, while holes gather on the wurtzite side, resulting in the creation of spatially separated indirect excitons with aligned dipoles. The perfectly flat polytype type-II interface serves to minimize scattering. Furthermore, modulation doping is implemented to reduce Coulomb scattering, achieved by doping the entire wurtzite segment n-type, excluding the vicinity of the interface. The investigation particularly focuses on understanding the impact of doping on the spatial distribution of indirect excitons at polytype type-II heterointerfaces. Spatially and temporally resolved photoluminescence spectroscopy at low temperatures is utilized to explore the spatial distribution andrecombination dynamics of indirect excitons. The study reveals a significantly reduced spatial distribution and enhanced recombination rate of indirect excitons in the presence of an electron background for the n-type doped platelets compared to the undoped platelets. This aligns with expectations due to enhanced recombination rates provided by numerous electrons. Additionally, we were able to estimate a lower limit for the expansion speed of the indirect excitons at high excitation power density in undoped platelets.