Rapid and Large-Scale Quality Assessment of Two-Dimensional MoS₂ Using Sulfur Particles with Optical Visualization

Abstract

The efficient nondestructive assessment of quality and homogeneity for two-dimensional (2D) MoS 2 is critically important to advance their practical applications. Here, we presented a rapid and large-area assessment method for visually evaluating the quality and uniformity of chemical vapor deposition (CVD)-grown MoS 2 monolayers simply with conventional optical microscopes. This was achieved through one-pot adsorbing abundant sulfur particles selectively onto as-grown poorer-quality MoS 2 monolayers in a CVD system without any additional treatment. We further revealed that this favorable adsorption of sulfur particles on MoS 2 originated from their intrinsic higherdensity sulfur vacancies. Based on unadsorbed MoS 2 monolayers, superior performance field effect transistors with a mobility of ∼49 cm 2 V −1 s −1 were constructed. Importantly, the assessment approach was noninvasive due to the all-vapor-phase and moderate adsorption−desorption process. Our work offers a new route for the performance and yield optimization of devices by quality assessment of 2D semiconductors prior to device fabrication.

Monitoring the Material Quality of Two-Dimensional Transition Metal Dichalcogenides

“…(d) Schematic of one-pot selective adsorption of sulfur particles directly on as-synthesized MoS 2 monolayers for rapid and large-scale quality assessment by optical visualization. Reproduced with permission from ref . Copyright 2021 American Chemical Society.…”

Strong Anisotropic Optical Properties by Rolling up MoS2 Nanoflake

“…Atomically two-dimensional (2D) materials display new physical and chemical properties owing to their strong light–matter interaction, dangling bond-free surface, tunable energy band structure, and strong mechanical flexibility. − All these unconventional advantages make them have broad application prospects in electronics, optoelectronics, catalysis, and energy storage. − Among all 2D materials, transition-metal dichalcogenides (TMDs) with higher mobility and wider bandgaps show favorable applications in electronic and photoelectronic devices. − MoS 2 as a typical layered TMDs material has been widely investigated. For example, a monolayer MoS 2 photodetector exhibits a broad spectral response with a maximum photoresponsivity of 880 A/W .…”

Defect-Rich Monolayer MoS2 as a Universally Enhanced Substrate for Surface-Enhanced Raman Scattering

“…Figure 1 a examines a series of advances centered on monolayer MoS 2 , including preparation, evaluation of MoS 2 containing defects, and characterization of various SERS properties. Sublimable sulfur powder and molybdenum foil were used to prepare monolayer MoS 2 in a CVD system, which was an improvement demonstrated in previous works [ 40 , 41 ]. The metallic molybdenum foil was electroplated and treated on an electrochemical workstation.…”

“…Here, for the first time, we use experiments and theory to investigate the Raman enhancement effect of monolayer MoS 2 before and after the presence of surface defects. In this paper, large-scale, highly crystalline samples were prepared under the precise control of the chemical vapor deposition (CVD) method with sulfur powder and electroplated molybdenum foil as precursors of the monolayer MoS 2 and with SiO 2 /Si as substrates [ 40 , 41 , 42 ]. Indeed, due to the strong fluorescence background and inefficient CT, it is difficult to visualize the SERS signal in perfect MoS 2 monolayers, especially when the surface contains low concentrations of detected molecules.…”