Document Type
Article
Publication Date
10-2024
Keywords
2D materials; biaxial strain; second-harmonicgeneration
Abstract
Nonlinear optical materials of atomic thickness, such as non-centrosymmetric 2H transition metal dichalcogenide monolayers, have a second-order nonlinear susceptibility (χ(2)) whose intensity can be tuned by strain. However, whether χ(2) is enhanced or reduced by tensile strain is a subject of conflicting reports. Here, we grow high-quality MoSe2 monolayers under controlled biaxial strain created by two different substrates and study their linear and nonlinear optical responses with a combination of experimental and theoretical approaches. Up to a 15-fold overall enhancement in second-harmonic generation (SHG) intensity is observed from MoSe2 monolayers grown on SiO2 when compared to its value on a Si3N4 substrate. By considering an interference contribution from different dielectrics and their thicknesses, a factor of 2 enhancement of χ(2) was attributed to the biaxial strain: substrate interference and strain are independent handles to engineer the SHG strength of non-centrosymmetric 2D materials.
Citation
Puri, S., Patel, S., Cabellos, J. L., Rosas-Hernandez, L. E., Reynolds, K., Churchill, H. O., Barraza-Lopez, S., Mendoza, B. S., & Nakamura, H. (2024). Substrate Interference and Strain in the Second-Harmonic Generation from MoSe2 Monolayers. Nano Letters, 24 (41), 13061-13067. https://doi.org/10.1021/acs.nanolett.4c03880
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