Few-layer MoS₂as nitrogen protective barrier

Abstract

We report experimental and theoretical investigations of the observed barrier behavior of few-layer MoS against nitrogenation. Owing to its low-strength shearing, low friction coefficient, and high lubricity, MoS exhibits the demeanor of a natural N-resistant coating material. Raman spectroscopy is done to determine the coating capability of MoS on graphene. Surface morphology of our MoS/graphene heterostructure is characterized by using optical microscopy, scanning electron microscopy, and atomic force microscopy. In addition, density functional theory-based calculations are performed to understand the energy barrier performance of MoS against nitrogenation. The penetration of nitrogen atoms through a defect-free MoS layer is prevented by a very high vertical diffusion barrier, indicating that MoS can serve as a protective layer for the nitrogenation of graphene. Our experimental and theoretical results show that MoS material can be used both as an efficient nanocoating material and as a nanoscale mask for selective nitrogenation of graphene layer.

Theoretical and experimental investigation of conjugation of 1,6-hexanedithiol on MoS2

“…MoS 2 solution and HDT molecule were mixed for an hour and incubated overnight. The thicknesses of MoS 2 flakes are similar as given in our previous study [35].…”

Thermal annealing effects on the electrophysical characteristics of sputtered MoS2 thin films by Hall effect measurements

“…As shown in figure 3(b), thermal annealing affects the quality of RT-sputtered MoS 2 thin films. The two characteristic Raman active modes [6,27,36] that correspond to the opposite vibration of two S atoms against the Mo atom (E 2g 1 ) and the vibration of only S atoms in the opposite direction (A 1g ) are invisible in the samples thermally annealed at 0 °C, 200 °C, and 400 °C. The MoS 2 bulk crystals are formed in RT-deposited and after low-temperature thermal annealing.…”

Determining the Molecular Orientation on the Metal Nanoparticle Surface through Surface-Enhanced Raman Spectroscopy and Density Functional Theory Simulations

“…Since the discovery of surface-enhanced Raman scattering (SERS) in the late 1970s, the technology has gained great attention from a broad spectrum of science, especially in the field of surface science, electrochemistry, biomedical science, environmental monitoring, and food analysis due to its high sensitivity, potential rapidity, and noninvasive nature. − The ultrasensitive approach for trace detection enables SERS to be a promising analytical tool, and in some instances, it is the only way to detect a single molecule and simultaneously probe its chemical structure for studying interfacial processes. − The SERS signals from single molecules were independently observed on nanoparticle aggregations by the groups of Nie and Kneipp. , The Raman enhancement effect is mainly attributed to surface plasmon resonance (SPR), which forms “hot spots” among adjacent metallic nanoparticles (NPs). − A great deal of research has been conducted for decades on substrate synthesis, leading to Ag-NPs, becoming the standard SERS active substrate, with an enhancement factor in excess of 10 6 . , In addition to Ag NPs, recently, other metallic nanomaterials such as Au NPs, Pt-NPs, Cu-NPs, and semiconductor nanomaterials ( e.g ., CdTe, ZnS, CuO) have been studied extensively because of their chemical and physical properties specifically their optical, electrical, and magnetic properties. − Among those nanomaterials, Ag-NPs display excellent performance in optical absorption, scattering signatures, and the SERS signals due to the electromagnetic enhancement, which is attributed to local surface plasmon resonances (LSPR) …”