Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 48: Poster: 2D Materials beyond Graphene: TMDCs, Silicene and Relatives
O 48.18: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Ellipsometric determination of the anisotropic refractive index of WSe2 via angle resolved measurements for E=1.89 eV — •Walter Enns1, Sergej Neb1, Sebastian Fiechter2, and Walter Pfeiffer1 — 1Universität Bielefeld, Fakultät für Physik, Universitätsstr. 25, 33615 Bielefeld, Germany — 2Helmholtz Zentrum Berlin, Institut für Solare Brennstoffe, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
Although the transition metal dichalcogenide (TMDC) van der Waals crystals are obviously optically anisotropic, little information is found in literature. Experimental determination of the optical anisotropic response is complicated by the preferential cleaving of crystals along the van der Waals gaps. In addition the formation of a contamination layer in air and the macroscopicly uneven surface are further experimental hurdles. Here it is shown that precise angle resolved ellipsometric single-wavelength measurements combined with statistical and error analysis enables extracting the complex anisotropic refractive index from the coupled ellipsometric values Δ and Ψ. The experimentally obtained values show reasonable agreement with theoretical calculations of the dielectric function [1, 2].
[1] S. Sharma, et al., Phys. Rev. B 60, 8610 (1999)
[2] A. Kumar, et al., Physica B: Condensed Matter 407, 24 (2012)