Chasing polaritons: A pathway to investigate the optoelectronic properties of van der Waals heterostructures

Principal investigators

  1. Patryk Kusch, Freie Universität Berlin, Fachbereich Physik, patryk.kusch (at) fu-berlin.de [webpage]
  2. Stephanie Reich, Freie Universität Berlin, Fachbereich Physik, sreich (at) zedat.fu-berlin.de [webpage]

teaser picture

Abstract

We aim to investigate the fundamental properties of interlayer excitons/trions in 2D van der Waals heterostructures using a wavelength-tunable near-field scanning optical microscope with visible laser excitation. We will nanoimage the propagation of interlayer polaritons in real space by recording near-field interference patterns with nanoscale resolution. The near-field images will enable us to visualize moiré patterns and study their influence on polariton propagation. Our experiments will be performed for various materials combinations and relative monolayer orientation. By combining nanoscale microscopy with far-field and near-field spectroscopy we will extract excitation energies, lifetimes, propagation length, and the coupling strength of light-matter interaction.

We apply several experimental methods including, excitation tunable scattering type scanning near-field microscopy, tip-enhanced Raman and photoluminescence spectroscopy, resonant Raman scattering, scanning transmission electron microscopy, chemical vapor deposition and mechanical exfoliation of 2D materials. The experiments will be supported by non-local Maxwell Bloch calculations and density functional theory.