Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 33: Optical Properties 2
HL 33.4: Vortrag
Donnerstag, 8. September 2022, 15:45–16:00, H32
Dielectric function of CuBrxI1-x thin films — •E. Krüger1, M. Seifert2, M. Bar1, S. Merker3, P. Bischoff1, H. Krautscheid3, S. Botti2, M. Grundmann1, and C. Sturm1 — 1Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Germany — 2Friedrich-Schiller-Universität Jena, Institut für Festkörpertheorie und -optik, Germany — 3Universität Leipzig, Institut für Anorganische Chemie, Germany
Copper halides such as CuI and CuBr are promising p-type semiconductors for transparent optoelectronic devices, especially due to the recently proposed hole density tunability [1]. Here, we present the dielectric function of CuBrxI1-x thin films (0≤ x≤1) determined by spectroscopic ellipsometry in the spectral range from 0.7 eV to 6.5 eV at room temperature. The observed features in the dielectric function are attributed to various electronic transitions in the Brillouin zone [2]. Non-monotonic behavior is observed for the band gap energy as a function of alloy composition revealing a quadratic bowing parameter of 0.5 in good agreement with literature [3]. The spin-orbit splitting decreases linearly from 650 meV for CuI to 150 meV for CuBr. The experimental results are compared with DFT-calculated band structures for different alloy compositions. The effects of bond length mismatches, chemical disorder, and different contributions of metal and halogen atoms to the upper valence bands are discussed in detail.
[1] Yamada et al., Adv. Funct. Mater. 30, 2003096 (2020)
[2] Krüger et al., APL 113, 172102 (2018)
[3] M. Cardona, Phys. Rev. 113, 69 (1963)