Substrate interference and strain in the second harmonic generation from MoSe${}_2$ monolayers

Abstract

Nonlinear optical materials of atomic thickness--such as non-centrosymmetric 2H transition metal dichalcogenide monolayers--have a second order nonlinear susceptibility (${\chi }^{(2)}$) whose intensity can be tuned by strain. However, whether ${\chi }^{(2)}$ is enhanced or reduced by tensile strain is a subject of conflicting reports. Here, we grow high-quality MoSe${}_2$ monolayers under controlled biaxial strain created by two different substrates, and study their linear and non-linear optical responses with a combination of experimental and theoretical approaches. A 15-fold overall enhancement in second harmonic generation (SHG) intensity is observed on MoSe${}_2$ monolayers grown on SiO${}_2$ when compared to its value when on a Si${}_3$N${}_4$ substrate. A seven-fold enhancement was ascertained to substrate interference, and a factor of two to the enhancement of ${\chi }^{(2)}$ arising from biaxial strain: substrate interference and strain are independent handles to engineer the SHG strength of non-centrosymmetric 2D materials.

References in corpus (8)

• Optimized norm-conserving Vanderbilt pseudopotentials
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Observation of Intense Second Harmonic Generation from MoS${}_2$ Atomic Crystals
• Second harmonic microscopy of monolayer MoS2
• Strain engineering in semiconducting two-dimensional crystals
• Optical imaging of strain in two-dimensional crystals
• Phonon Softening and Direct to Indirect Bandgap Crossover in Strained Single Layer MoSe2
• All-optical polarization and amplitude modulation of second-harmonic generation in atomically thin semiconductors

Cited by in corpus (6)

• Biaxial strain tuning of excitons in monolayer MoSe${}_2$ by high-temperature physical vapor deposition
• Probing quantum geometric nonlinear magnetization via second-harmonic magneto-optical Kerr effect
• Visible and Terahertz Nonlinear Responses in the Topological Noble Metal Dichalcogenide PdTe2
• Perturbative second-order optical susceptibility of bulk materials: a symmetry-enforced return to non-orthogonal localized basis sets
• Tuning Terahertz Optomechanics of MoS2 Bilayers with Homogeneous In-plane Strain
• Nonlinear Anisotropy in Phase-Tuned Wide-Gap Halides