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Geometrical Engineering of Giant Optical Dichroism in Rippled MoS 2 Nanosheets
Author(s) -
Mennucci Carlo,
Mazzanti Andrea,
Martella Christian,
Lamperti Alessio,
Bhatnagar Mukul,
Lo Savio Roberto,
Repetto Luca,
Camellini Andrea,
ZavelaniRossi Margherita,
Molle Alessandro,
Buatier de Mongeot Francesco,
Della Valle Giuseppe
Publication year - 2021
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202001408
Subject(s) - materials science , curvature , anisotropy , dichroism , photoluminescence , dielectric , extinction (optical mineralogy) , optoelectronics , optics , molecular physics , geometry , physics , mathematics
A cost effective method to tailor the optical response of large‐area nanosheets of 2D materials is described. A reduced effective metalayer model is introduced to capture the key‐role of the out‐of‐plane component of the dielectric tensor. Such a model indicates that the optical extinction of 2D materials can be strongly altered by controlling the geometry at the local (i.e., subwavelength) scale. In particular, a giant linear optical dichroism at normal incidence is demonstrated, with major features around the excitonic peaks, that can be tailored by acting on the average curvature and slope of the nanosheets. The approach is experimentally demonstrated in few‐layer MoS 2 grown by chemical vapor deposition on cm‐scale anisotropic nanopatterned substrates prepared by a self‐assembling technique, based on defocused ion beam sputtering. Major variations in the photoluminescence spectrum as a function of the average curvature and slope are also revealed. A full‐vectorial numerical study beyond the effective metalayer model and comprising strain effects induced by the geometry turns out to be consistent with such a complex scenario. The results demonstrate that the extrinsic geometrical engineering definitely opens viable way to tailor the optical properties and modulate bandgap of low dimensional materials.