Simultaneous Generation of Direct- and Indirect-Gap Photoluminescence in Multilayer MoS2 Bubbles

Abstract

Transition metal dichalcogenide (TMD) materials have received enormous attention due to their extraodinary optical and electrical properties, among which MoS2 is the most typical one. As thickness increases from monolayer to multilayer, the photoluminescence (PL) of MoS2 is gradually quenched due to the direct-to-indirect band gap transition. How to enhance PL response and decrease the layer dependence in multilayer MoS2 is still a challenging task. In this work, we report, for the first time, simultaneous generation of three PL peaks at around 1.3, 1.4 and 1.8 eV on multilayer MoS2 bubbles. The temperature dependent PL measurements indicate that the two peaks at 1.3 and 1.4 eV are phonon-assisted indirect-gap transitions while the peak at 1.8 eV is the direct-gap transition. Using first-principles calculations, the band structure evolution of multilayer MoS2 under strain is studied, from which the origin of the three PL peaks of MoS2 bubbles is further confirmed. Moreover, PL standing waves are observed in MoS2 bubbles that creates Newton-Ring-like patterns. This work demonstrates that the bubble structure may provide new opportunities for engineering the electronic structure and optical properties of layered materials.

References in corpus (19)

• The Raman Fingerprint of Graphene
• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
• Bandgap Engineering of Strained Monolayer and Bilayer MoS2
• Local strain engineering in atomically thin MoS2
• Experimental demonstration of continuous electronic structure tuning via strain in atomically thin MoS2
• The Shear Mode of Multi-Layer Graphene
• Interlayer breathing and shear modes in few-trilayer MoS2 and WSe2
• Band Gap Engineering with Ultralarge Biaxial Strains in Suspended Monolayer MoS2
• Origin of indirect optical transitions in few-layer MoS2, WS2 and WSe2
• Shear and Layer Breathing Modes in Multilayer MoS2
• Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS2
• Graphene bubbles on a substrate : Universal shape and van der Waals pressure
• The Interlayer Shear Modes in Twisted Multi-layer Graphenes: Interlayer coupling, Davydov Splitting and Intensity Resonance
• Strained bubbles in van der Waals heterostructures as local emitters of photoluminescence with adjustable wavelength
• Low-Frequency Raman Modes and Electronic Excitations In Atomically Thin MoS2 Crystals
• Strain-shear coupling in bilayer MoS2
• Proton-driven patterning of bulk transition metal dichalcogenides
• Isolating hydrogen in hexagonal boron nitride bubbles by a plasma treatment
• Intrinsic properties of suspended MoS2 on SiO2/Si pillar arrays for nanomechanics and optics

Cited by in corpus (2)

• Two-dimensional crystals on adhesive substrates subjected to uniform transverse pressure
• Nonlinear exciton drift in piezoelectric two-dimensional materials