Regensburg 2019 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 7: Optical Analysis of Thin Films II (Reflection, Ellipsometry, Raman, IR-DUV Spectroscopy, ...
DS 7.5: Vortrag
Montag, 1. April 2019, 16:00–16:15, H32
Tailoring the optical properties of atomically-thin tungsten disulfide via ion irradiation — •Linan Ma1, Yang Tan1, Mahdi Ghorbani-Asl2, Shengqiang Zhou2, Arkady V Krasheninnikov2, and Feng Chen1 — 1School of Physics, Shandong University, Jinan, China — 2Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam and Materials Research, Dresden, Germany
Two-dimensional transition metal dichalcogenides exhibit excellent optoelectronic properties. However, the large band gaps in many semiconducting transition metal dichalcogenides make optical absorption in the near-infrared wavelength Regime impossible, which prevents applications of these materials in optical communications. In this work, we demonstrate that Ar ion irradiation is a powerful post-synthesis technique to tailor the optical properties of the semiconducting tungsten disulfide by creating S-vacancies and thus controlling material stoichiometry. First-principles calculations reveal that the S-vacancies give rise to deep states in the band gap, which determine the near-infrared optical absorption of the tungsten disulfide monolayer. As the density of the S-vacancies increases, the enhanced the near-infrared linear and saturable absorption of tungsten disulfide is observed, which is explained by the results of first-principles calculations. We further demonstrate that by using the irradiated tungsten disulfide as a saturable absorber in a waveguide system, the passively Q-switched laser operations can be optimized, thus opening new avenues for tailoring the optical response of transition metal dichalcogenides by defect-engineering through ion irradiation.