Optical investigation of the natural electron doping in thin MoS2 films deposited on dielectric substrates

Abstract

Two-dimensional (2D) compounds provide unique building blocks for novel layered devices and hybrid photonic structures. However, large surface-to-volume ratio in thin films enhances the significance of surface interactions and charging effects requiring new understanding. Here we use micro-photoluminescence (PL) and ultrasonic force microscopy to explore the influence of the dielectric environment on optical properties of a few monolayer MoS2 films. PL spectra for MoS2 films deposited on SiO2 substrates are found to vary widely. This film-to-film variation is suppressed by additional capping of MoS2 with SiO2 and SiN, improving mechanical coupling of MoS2 with surrounding dielectrics. We show that the observed PL non-uniformities are related to strong variation in the local electron charging of MoS2 films. In completely encapsulated films, negative charging is enhanced leading to uniform optical properties. Observed great sensitivity of optical characteristics of 2D films to surface interactions has important implications for optoelectronics applications of layered materials.

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References in corpus (11)

• Two Dimensional Atomic Crystals
• Valley polarization in MoS2 monolayers by optical pumping
• Bandgap Engineering of Strained Monolayer and Bilayer MoS2
• Local strain engineering in atomically thin MoS2
• Symmetry-dependent phonon renormalization in monolayer MoS2 transistor
• Experimental demonstration of continuous electronic structure tuning via strain in atomically thin MoS2
• Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS2
• Robust optical emission polarization in MoS2 monolayers through selective valley excitation
• Enhancement of Carrier Mobility in Semiconductor Nanostructures by Dielectric Engineering
• Visibility of dichalcogenide nanolayers
• Photoluminescence of freestanding single- and few-layer MoS2

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