Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 76: Plasmonics and Nanooptics III: Light-Matter Interaction and Spectroscopy II
O 76.7: Talk
Thursday, March 30, 2023, 12:00–12:15, WIL A317
Luminescence from Cu2O films and bulk crystals in the STM — Alexander Gloystein, Mina Soltanmohammadi, and •Niklas Nilius — Carl von Ossietzky Universität, Institut für Physik, D-26111 Oldenburg, Germany
STM luminescence spectroscopy is employed to compare the optical response of bulk Cu2O(111) and 1-10 nm thick Cu2O/Au(111) films. Although both systems share similar structural and electronic properties and expose the same thermodynamically preferred (√3× √3)R30∘ reconstruction, their luminescence exhibits pronounced differences. The spectra of bulk Cu2O are dominated by the recombination of free and defect-bound excitons, whereas a unique plasmonic response is detected for the oxide films. The latter arises from the electromagnetic coupling between STM tip and gold support, while the Cu2O ad-layer exclusively controls the inelastic tunneling rates, i.e., the intensity, but not the spectral signature of the emission. Only upon tunneling into the Cu2O band gap, a luminescence channel mediated by O vacancies is identified in the oxide film. The talk addresses the question why the unique exciton response of Cu2O is covered by plasmon excitations even in films as thick as 10 nm.