The in-situ observation is of great significance to the study of the growth mechanism and controllability of two-dimensional transition metal dichalcogenides (TMDCs). Here, the differential reflectance spectroscopy (DRS) was performed to monitor the growth of molybdenum disulfide (MoS) on a SiO/Si substrate prepared by chemical vapor deposition (CVD). A home-built in-situ DRS setup was applied to monitor the growth of MoS in-situ. The formation and evolution of monolayer MoS are revealed by differential reflectance (DR) spectra. The morphology, vibration mode, absorption characteristics and thickness of monolayer MoS have been confirmed by optical microscopy, Raman spectroscopy, ex-situ DR spectra, and atomic force microscopy (AFM) respectively. The results demonstrated that DRS was a powerful tool for in-situ observations and has great potential for growth mechanism and controllability of TMDCs prepared by CVD. To the best of the authors' knowledge, it was the first report in which the CVD growth of two-dimensional TMDCs has been investigated in-situ by reflectance spectroscopy.
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http://dx.doi.org/10.3390/nano9111640 | DOI Listing |
ACS Nano
January 2025
School of Engineering, RMIT University, 124 La Trobe Street, Melbourne, Victoria 3001, Australia.
Modern-day applications demand onboard electricity generation that can be achieved using piezoelectric phenomena. Reducing the dimensionality of materials is a pathway to enhancing the piezoelectric properties. Transition-metal dichalcogenides have been shown to exhibit high piezoelectricity.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Dep. Fisica, Universidade Federal de Minas Gerais, ICEX, Av. Antonio Carlos 6627, Belo Horizonte, MG, 31270-901, BRAZIL.
Nowadays, experimental research advances in condensed matter physics are deep-rooted in the development and manipulation of nanomaterials, making it essential to explore the fundamental properties of materials that are candidates for nanotechnology. In this work, we study the dependence of the molybdenum disulfide (MoS2) Raman modes on the sample temperature and on the excitation laser power. From the correlation between these two sets of measurements, we determine the planar thermal conductivity of MoSmonolayers, bilayers, trilayers, four layers, seven layers, and eight layers.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, United States.
A spin valve represents a well-established device concept in magnetic memory technologies, whose functionality is determined by electron transmission, controlled by the relative alignment of magnetic moments of the two ferromagnetic layers. Recently, the advent of valleytronics has conceptualized a valley spin valve (VSV)─a device that utilizes the valley degree of freedom and spin-valley locking to achieve a similar valve effect without relying on magnetism. In this study, we propose a nonvolatile VSV (-VSV) based on a two-dimensional (2D) ferroelectric semiconductor where resistance of -VSV is controlled by a ferroelectric domain wall between two uniformly polarized domains.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China. Electronic address:
Currently, the development of high-performance adsorbents for the removal of nanoplastics in complex aquatic environments is challenging. In this study, a functionalized polyethyleneimine-phosphorylated microcrystalline cellulose/MoS (PEI-PMCC/MoS) hybrid aerogel was prepared and applied to remove carboxyl-modified polystyrene (PS-COOH) nanoplastics from the aqueous solution. Benefiting from the introduced functional groups and the expanded lamellar structure in MoS nanosheets as well as the highly porous 3D structure of the aerogel, PEI-PMCC/MoS demonstrated high efficiency in PS-COOH nanoplastics removal, achieving a 402.
View Article and Find Full Text PDFNat Mater
January 2025
Academy for Advanced Interdisciplinary Science and Technology, Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of Education, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, P. R. China.
Batch production of single-crystal two-dimensional (2D) transition metal dichalcogenides is one prerequisite for the fabrication of next-generation integrated circuits. Contemporary strategies for the wafer-scale high-quality crystallinity of 2D materials centre on merging unidirectionally aligned, differently sized domains. However, an imperfectly merged area with a translational lattice brings about a high defect density and low device uniformity, which restricts the application of the 2D materials.
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