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Proceedings Paper

2D materials under the microscope(s): connecting material properties and electronic structure to many-body excitonic phenomena in monolayer WS2 (Conference Presentation)
Author(s): Christoph Kastl; Roland Koch; Chris Chen; Johanna Eichhorn; Bruno Schuler; Tev Kuykendall; Simon Moser; Aaron Bostwick; Chris Jowiak; Shaul Aloni; Alexander Weber-Bargioni; Eli Rotenberg; Adam M. Schwartzberg
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Paper Abstract

Interest in transition metal dichalcogenides has been renewed by the discovery of emergent properties when reduced to single, two-dimensional (2D) layers. In the few-layer limit, the optical and electronic properties of TMDs are modified by a strongly reduced dielectric screening. As a consequence of the weak screening, these 2D materials are intrinsically susceptible to spatial disorder, which can arise due to defects from the growth or interactions with the substrate. Here, we use a set of complementary imaging techniques - Raman, photoluminescence, Kelvin probe, and photoelectron spectroscopy – to correlate locally the chemical state, electronic structure, and optical properties of 2D transition metal dichalcogenides. In particular, we employ spatially resolved angle resolved photoemission spectroscopy (nano-ARPES) to map the variations in band alignment, effective mass and chemical composition of CVD-grown monolayer WS2. By correlating the spectroscopic information from nano-ARPES with hyperspectral photoluminescence data, we reveal the interplay between local material properties, such as defect density or chemical composition, and the formation of charged trions, defect-bound excitons and neutral excitons. We compare these results to combined atomic force and scanning tunneling microscopy studies, where we can unambiguously identify point defects in the films at the atomic level.

Paper Details

Date Published: 14 March 2018
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Proc. SPIE 10534, 2D Photonic Materials and Devices, 1053404 (14 March 2018); doi: 10.1117/12.2291217
Show Author Affiliations
Christoph Kastl, Lawrence Berkeley National Lab. (United States)
Roland Koch, Lawrence Berkeley National Lab. (United States)
Chris Chen, Lawrence Berkeley National Lab. (United States)
Johanna Eichhorn, Lawrence Berkeley National Lab. (United States)
Bruno Schuler, Lawrence Berkeley National Lab. (United States)
Tev Kuykendall, Lawrence Berkeley National Lab. (United States)
Simon Moser, Lawrence Berkeley National Lab. (United States)
Aaron Bostwick, Lawrence Berkeley National Lab. (United States)
Chris Jowiak, Lawrence Berkeley National Lab. (United States)
Shaul Aloni, Lawrence Berkeley National Lab. (United States)
Alexander Weber-Bargioni, Lawrence Berkeley National Lab. (United States)
Eli Rotenberg, Lawrence Berkeley National Lab. (United States)
Adam M. Schwartzberg, Lawrence Berkeley National Lab. (United States)


Published in SPIE Proceedings Vol. 10534:
2D Photonic Materials and Devices
Arka Majumdar; Xiaodong Xu; Joshua R. Hendrickson, Editor(s)

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