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Two-dimensional (2D) materials with atomic thickness are promising candidates for the applications in future semiconductor devices, owing to their fascinating physical properties and superlative optoelectronic performance. Chemical vapor deposition (CVD) is considered to be an efficiënt method for large-scale preparation of 2D materials toward practical applications. However, the high melting points of metal precursors and the thermodynamics instabilities of metastable phases limit the direct CVD synthesis of plenty of 2D materials. The salt has recently been introduced into the CVD process, which proved to be effective to address these issues. In this review, we highlighted the latest progress in the salt-assisted CVD growth of 2D materials, including layered and non-layered crystals. Firstly, strategies of adding salts are summarized. Then, the salt-assisted growth of various layered materials is presented, emphasizing on the transition metal chalcogenides of stable and metastable phases. Furthermore, strategies to grow ultrathin non-layered materials are discussed. We provide viewpoints into the techniques of using salt, the effects of salt, and the growth mechanisms of 2D crystals. Finally, we offer the challenges to be overcome and further research directions of this emerging salt-assisted CVD technique. [ABSTRACT FROM AUTHOR]

A controllable elemental substitution strategy enables the strain engineering of two-dimensional MoS 2 to its limit, which can potentially modulate its physical and chemical properties and broaden its applications. [Display omitted] Strain engineering is a promising method for tuning the electronic properties of two-dimensional (2D) materials, which are capable of sustaining enormous strain thanks to their atomic thinness. However, applying a large and homogeneous strain on these 2D materials, including the typical semiconductor MoS 2 , remains cumbersome. Here we report a facile strategy for the fabrication of highly strained MoS 2 via chalcogenide substitution reaction (CSR) of MoTe 2 with lattice inheritance. The MoS 2 resulting from the sulfurized MoTe 2 sustains ultra large in-plane strain (approaching its strength limit ~10%) with great homogeneity. Furthermore, the strain can be deterministically and continuously tuned to ~1.5% by simply varying the processing temperature. Thanks to the fine control of our CSR process, we demonstrate a heterostructure of strained MoS 2 /MoTe 2 with abrupt interface. Finally, we verify that such a large strain potentially allows the modulation of MoS 2 bandgap over an ultra-broad range (~1 eV). Our controllable CSR strategy paves the way for the fabrication of highly strained 2D materials for applications in devices. [ABSTRACT FROM AUTHOR]