Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 13: Poster I
HL 13.14: Poster
Monday, March 18, 2024, 15:00–18:00, Poster E
Resonant Raman scattering at split-off band exciton in CuI — •R. Hildebrandt1, S. Blaurock2, H. Krautscheid2, M. Grundmann1, and C. Sturm1 — 1Universität Leipzig, Felix Bloch Institute for Solid State Physics, Germany — 2Universität Leipzig, Institute of Inorganic Chemistry, Germany
We investigate the resonant Raman spectrum of copper iodide (CuI), and observed up to ten consecutive LO-phonon scattering processes for the split-off band exciton. This exciton is energetically isolated and located above the fundamental bandgap. The resonance condition is varied by using excitation wavelengths of 355 nm, 325 nm and 320 nm, which are located above and below the respective exciton energy of 335nm.
This resonant interaction of excitons and phonons is mediated via the Fröhlich interaction and can give access to fundamental material characteristics such as effective masses, electron-phonon coupling and their wave-vector dependence. Dipole-forbidden transitions can be investigated or localized modes can be used for precise determination of doping concentrations [1]. The observed multiple LO-phonon scattering processes are typical for polar semiconductors[2] and contain information for exciton damping constants, relaxation times as well as acoustic phonon dispersion characteristics [3]. The therewith-derived properties of CuI will be discussed in this work.
[1] Y. Zhang, J. Semicond., 40, 091102, 2019.
[2] R. Leite, J., Phys. Lett., 22, 780, 1969.
[3] P. Yu and M. Cardona, Fundamentals of Semiconductors, 2010.
Keywords: Resonant Raman Scattering; Wide-Bandgap Semiconductor; Phonons; Excitons