Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 39: Quantum Dots and Wires 6: II-VI and related
HL 39.1: Vortrag
Freitag, 9. September 2022, 09:30–09:45, H32
Raman and X-ray photoemission study of thin films of binary and ternary semiconductor quantum dots — •Oleksandr Selyshchev1,2, Volodymyr Dzhagan3,4, and Dietrich R.T. Zahn1,2 — 1Semiconductor Physics, TU Chemnitz, Germany — 2Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), TU Chemnitz, Germany — 3Institute of Semiconductors Physics, NAS of Ukraine, Kyiv, Ukraine — 4Taras Shevchenko National University of Kyiv, Ukraine
Quantum dots (QDs) of ternary semiconductor chalcogenides MInS2 (M = Cu, Ag) attract attention as environment friendly alternatives to toxic cadmium and lead chalcogenides. Even though both ternary and binary QDs exhibit size dependent absorption and photoluminescence spectra, the properties of ternary compounds additionally depend on composition, variety of crystalline phases, and defects. Here, we present a comparative Raman and X-ray photoemission spectroscopic (XPS) study of thin films of binary CdS and ternary MInS2 QDs to examine their structural and electronic properties. Raman results show that MInS2 QDs co-exist in chalcopyrite and Cu-Au type phases. XPS study revealed indium-rich surface deviating from ideal stoichiometry. Auger parameters confirm metal ions in the expected oxidation states, while the boundary states of sulfur indicate surface passivation through the thiolate group of thioglycolate ligands. The ionization potentials of binary and ternary QDs are found to be the same as those for the bulk indicating that the bandgap increase is due to quantum confinement of electrons in the conduction band.