Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.49: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

Optimisation of pulsed-laser-deposition-grown CuI polariton microcavities — Kirsty E. McGhee, Lukas Trefflich, Aaron Giess, Marius Grundmann, and •Chris Sturm — Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Germany

Exciton-polaritons are light-matter quasiparticles that possess properties of both excitons and photons, making them of great interest for ultra-low threshold lasers, all-optical circuits, and quantum simulators. Because excitons and photons are both bosons, polaritons are also bosons and, under certain conditions, can undergo a non-equilibrium Bose-Einstein-like condensation. In this work, we discuss our efforts to realise polariton condensation in a microcavity containing copper iodide (CuI), a transparent semiconductor currently of great interest due to its inherent p-type behaviour. We discuss the optimisation of the growth of the CuI layer and of the distributed Bragg reflectors (DBRs), the highly-reflective mirrors used to confine the cavity mode, using pulsed laser deposition. In particular, we have found adhesion problems between CuI and the low-refractive-index dielectrics Al2O3 and MgO (n∼1.7). These adhesion problems disappear when we instead grow the CuI between layers of yttria-stabilised zirconia (YSZ, n∼2.1). However, while we demonstrate the presence of exciton-polaritons, we do not see any evidence of polariton condensation at room temperature or cryogenic temperatures, likely due to the low cavity quality factor. In order to enhance this quality factor, further optimisation is required, which will be presented here.

Keywords: polaritons; copper iodide; microcavity; pulsed laser deposition; poalriton condensation