Excitons in cuprous oxide micro- and nanocrystals

Cuprous oxide (Cu2O) is a metal oxide semiconductor with unique characteristics and high relevance in applications such as photovoltaics, solar water splitting and photocatalysis. The optical properties are governed by excitons, i.e. quasi-particles arising from electron-hole Coulomb interactions, which show large binding energy and long lifetime. In particular, Rydberg excitons with high quantum numbers as well as spectroscopic signatures of quantum degeneracy of the exciton gas have been reported at cryogenic temperatures.

High-quality cuprous oxide microcrystals exhibiting photoluminescence from Rydberg excitons

In the Quantum Nano Photonics group, we study different aspects of Cu2O micro- and nanocrystals:

  • Quantum optics experiments with ground-state excitons and Rydberg states.

  • Optimized growth processes for controlling defects and doping.

  • Novel device concepts for chemical sensing of environmental pollutants.

We acknowledge funding from the Swedish Research Council (VR Starting Grant), Formas (Project Grant for Early-Career Researchers) and ÅForsk (Young Scientist Research Grant).

S. Steinhauer et al., Rydberg excitons in Cu2O microcrystals grown on a silicon platform. Communications Materials 1, 11 (2020).

Students interested in this topic are welcome to contact Dr. Stephan Steinhauer

( ssteinh@kth.se ).

Projects include material growth, cleanroom fabrication, photoluminescence spectroscopy down to milli-Kelvin temperatures and computational modelling.