Project Details
Projekt
Micro-PLE spectrometer with tunable laser
Subject Area
Condensed Matter Physics
Term
Funded in 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 563482208
The proposed setup is a micro-photoluminescence excitation spectrometer (PLE) for tunable excitation and detection of photoluminescence from the visible to the near-infrared spectral range, where the excitation source is a tunable narrow-band laser. The setup will be used for spatially resolved spectroscopy of novel two-dimensional (2D) materials, 1D carbon nanotubes and nanoribbons as well as semiconductor nanoparticles (0D). In 2D semiconductors and van der Waals (vdW) heterostructures, optical excitations can be controlled by a variety of effects: number of layers, defects and strain, or the combination of materials with different bandgaps, leading to the formation of interlayer excitons. Moreover, the weak vdW interaction between the layers offers an additional degree of freedom: the twist angle between the layers, which leads to the formation of a moiré potential, structural reconstructions, and/or hybridization of the electronic states with new fascinating properties. The overlap of the electronic wave functions with neighboring layers is often decisive for the electronic and vibronic interaction between the layers and thus for the resulting properties of the system. Optical spectroscopy, especially PLE, can provide important insights into understanding these interactions. We will use PLE to investigate the excitonic properties and interlayer interactions in 2D semiconductors by determining resonances in energetically higher optical excitations, by investigating relaxation channels to interlayer excitons and intermediate states, and by analyzing energy/exciton and charge transfer across vertical and lateral interfaces. For this purpose, it is necessary to perform spatially resolved lateral scans of the sample surface and PLE measurements at cryogenic temperatures. The excitation source must be a narrow-band cw laser, which can be continuously tuned in the visible and near-infrared spectral range, matching the energies of the excited excitons in 2D materials. In addition, the laser can then also be used for resonant Raman scattering: with resonant (tunable) Raman scattering, we will determine optical absorption profiles and electron-phonon coupling in nanoparticles, graphene nanoribbons as well as in semiconducting and metallic 2D materials and their heterostructures. The proposed micro-PLE spectrometer with tunable excitation laser will thus be essential for our future research.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Mikro-PLE-Spektrometer mit durchstimmbarem Laser
Instrumentation Group
1850 Spektralfluorometer, Lumineszenz-Spektrometer (außer Filterfluorometer
Applicant Institution
Friedrich-Alexander-Universität Erlangen-Nürnberg
