Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 25: Poster 1
HL 25.45: Poster
Mittwoch, 7. September 2022, 18:00–20:00, P2
Two-Photon Absorption Induced Photoluminescence in CuI Single Crystals — •Andreas Müller1, Evgeny Krüger1, Lukas Trefflich1, Steffen Blaurock2, Harald Krautscheid2, Marius Grundmann1, and Chris Sturm1 — 1Felix-Bloch-Institut für Festkörperphysik, Universität Leipzig — 2Institut für Anorganische Chemie, Universität Leipzig
The intrinsically p-type copper iodide (CuI) with a direct band gap of 2.95 eV at 300 K  and high exciton binding energy is a promising material for transparent semiconductor devices. The photoluminescence (PL) emission properties of CuI crystals have been recently reported . However, the PL emission induced by two-photon absorption (TPA-PL) has not been discussed in detail, so far.
We report on TPA-PL phenomena in CuI single crystals. A redshift compared to the conventional PL emission was observed. The TPA-PL spectrum can be nicely described by means of a simplified approach which takes into account the internal emission spectrum at the focal point, the propagation of the emitted photons inside the crystal and the absorption coefficient of CuI (determined by ellipsometry and taken from ). For the entire TPA-PL intensity we observed a non-linear power dependence, namely I ∝ P γ. The exponent γ depends on the excitation wavelength and ranges from 2 (expected for TPA-PL excitation via a virtual state) down to 1.5. The latter value was justified by a two-step TPA-PL process via a real state i.e. defect level.
 M. Grundmann et al., Phys. Status Solidi A 210, 1671 (2013)
 E. Krüger et al., APL Mater. 9, 121102 (2021)