Open AccessLocal Optical Properties in CVD-Grown Monolayer WS2 Flakes
Author(s) -
Michele Magnozzi,
Theo Pflug,
Marzia Ferrera,
Simona Pace,
Lorenzo Ramò,
Markus Olbrich,
Paolo Canepa,
Hasret Ağırcan,
Alexander Horn,
Stiven Forti,
Ornella Cavalleri,
Camilla Coletti,
Francesco Bisio,
M. Canepa
Publication year - 2021
Publication title -
journal of physical chemistry. c./journal of physical chemistry. c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.1c04287
Subject(s) - monolayer , photoluminescence , exciton , absorption (acoustics) , ellipsometry , chemical vapor deposition , materials science , spectroscopy , absorption spectroscopy , dielectric , radiative transfer , molecular physics , optoelectronics , chemical physics , thin film , optics , chemistry , nanotechnology , condensed matter physics , physics , composite material , quantum mechanics
Excitons dominate the light absorption and re-emission spectra of monolayer transition-metal dichalcogenides (TMD). Microscopic investigations of the excitonic response in TMD almost invariably extract information from the radiative recombination step, which only constitutes one part of the picture. Here, by exploiting imaging spectroscopic ellipsometry (ISE), we investigate the spatial dependence of the dielectric function of chemical vapor deposition (CVD)-grown WS 2 flakes with a microscopic lateral resolution, thus providing information about the spatially varying, exciton-induced light absorption in the monolayer WS 2 . Comparing the ISE results with imaging photoluminescence spectroscopy data, the presence of several correlated features was observed, along with the unexpected existence of a few uncorrelated characteristics. The latter demonstrates that the exciton-induced absorption and emission features are not always proportional at the microscopic scale. Microstructural modulations across the flakes, having a different influence on the absorption and re-emission of light, are deemed responsible for the effect.