Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide

Abstract We report strong second-harmonic generation (SHG) from 2H polytype of multilayer Tin diselenide (SnSe2) for fundamental excitation close to the indirect band-edge in the absence of excitonic resonances. Comparison of SHG and Raman spectra from exfoliated SnSe2 flakes of different polytypes...

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Autores principales:	Rabindra Biswas, Medha Dandu, Asish Prosad, Sarthak Das, Sruti Menon, Jayanta Deka, Kausik Majumdar, Varun Raghunathan
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/75e7cd6c58814a85a9cebf9cb2bfe7c0
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spelling	oai:doaj.org-article:75e7cd6c58814a85a9cebf9cb2bfe7c02021-12-02T16:17:22ZStrong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide10.1038/s41598-021-94612-82045-2322https://doaj.org/article/75e7cd6c58814a85a9cebf9cb2bfe7c02021-07-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-94612-8https://doaj.org/toc/2045-2322Abstract We report strong second-harmonic generation (SHG) from 2H polytype of multilayer Tin diselenide (SnSe2) for fundamental excitation close to the indirect band-edge in the absence of excitonic resonances. Comparison of SHG and Raman spectra from exfoliated SnSe2 flakes of different polytypes shows strong (negligible) SHG and Raman Eg mode at 109 cm−1 (119 cm−1), consistent with 2H (1T) polytypes. The difference between the A1g–Eg Raman peak positions is found to exhibit significant thickness dependent for the 1T form, which is found to be absent for the 2H form. The observed thickness dependence of SHG with rapid oscillations in signal strength for small changes in flake thickness are in good agreement with a nonlinear wave propagation model considering nonlinear polarization with alternating sign from each monolayer. The nonlinear optical susceptibility extracted from SHG signal comparison with standard quartz samples for 1040 nm excitation is found to be more than 4-times higher than that at 1550 nm. This enhanced nonlinear response at 1040 nm is attributed to the enhanced nonlinear optical response for fundamental excitation close to the indirect band-edge. We also study SHG from heterostructures of monolayer MoS2/multilayer SnSe2 which allows us to unambiguously compare the nonlinear optical response of SnSe2 with MoS2. We find the SHG signal and any interference effect in the overlap region to be dominated by the SnSe2 layer for the excitation wavelengths considered. The comparison of SHG from SnSe2 and MoS2 underscores that the choice of the 2D material for a particular nonlinear optical application is contextual on the wavelength range of interest and its optical properties at those wavelengths. The present works further highlights the usefulness of near band-edge enhancement of nonlinear processes in emerging 2D materials towards realizing useful nanophotonic devices.Rabindra BiswasMedha DanduAsish ProsadSarthak DasSruti MenonJayanta DekaKausik MajumdarVarun RaghunathanNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-12 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Rabindra Biswas Medha Dandu Asish Prosad Sarthak Das Sruti Menon Jayanta Deka Kausik Majumdar Varun Raghunathan Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide
description	Abstract We report strong second-harmonic generation (SHG) from 2H polytype of multilayer Tin diselenide (SnSe2) for fundamental excitation close to the indirect band-edge in the absence of excitonic resonances. Comparison of SHG and Raman spectra from exfoliated SnSe2 flakes of different polytypes shows strong (negligible) SHG and Raman Eg mode at 109 cm−1 (119 cm−1), consistent with 2H (1T) polytypes. The difference between the A1g–Eg Raman peak positions is found to exhibit significant thickness dependent for the 1T form, which is found to be absent for the 2H form. The observed thickness dependence of SHG with rapid oscillations in signal strength for small changes in flake thickness are in good agreement with a nonlinear wave propagation model considering nonlinear polarization with alternating sign from each monolayer. The nonlinear optical susceptibility extracted from SHG signal comparison with standard quartz samples for 1040 nm excitation is found to be more than 4-times higher than that at 1550 nm. This enhanced nonlinear response at 1040 nm is attributed to the enhanced nonlinear optical response for fundamental excitation close to the indirect band-edge. We also study SHG from heterostructures of monolayer MoS2/multilayer SnSe2 which allows us to unambiguously compare the nonlinear optical response of SnSe2 with MoS2. We find the SHG signal and any interference effect in the overlap region to be dominated by the SnSe2 layer for the excitation wavelengths considered. The comparison of SHG from SnSe2 and MoS2 underscores that the choice of the 2D material for a particular nonlinear optical application is contextual on the wavelength range of interest and its optical properties at those wavelengths. The present works further highlights the usefulness of near band-edge enhancement of nonlinear processes in emerging 2D materials towards realizing useful nanophotonic devices.
format	article
author	Rabindra Biswas Medha Dandu Asish Prosad Sarthak Das Sruti Menon Jayanta Deka Kausik Majumdar Varun Raghunathan
author_facet	Rabindra Biswas Medha Dandu Asish Prosad Sarthak Das Sruti Menon Jayanta Deka Kausik Majumdar Varun Raghunathan
author_sort	Rabindra Biswas
title	Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide
title_short	Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide
title_full	Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide
title_fullStr	Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide
title_full_unstemmed	Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide
title_sort	strong near band-edge excited second-harmonic generation from multilayer 2h tin diselenide
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/75e7cd6c58814a85a9cebf9cb2bfe7c0
work_keys_str_mv	AT rabindrabiswas strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT medhadandu strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT asishprosad strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT sarthakdas strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT srutimenon strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT jayantadeka strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT kausikmajumdar strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide AT varunraghunathan strongnearbandedgeexcitedsecondharmonicgenerationfrommultilayer2htindiselenide
_version_	1718384237937164288

Strong near band-edge excited second-harmonic generation from multilayer 2H Tin diselenide

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