Anisotropic 2D layered material rhenium disulfide (ReS2 ) with high crystal quality and uniform monolayer thickness is synthesized by using tellurium-assisted epitaxial growth on mica substrate. Benefit from the lower eutectic temperature of rhenium-tellurium binary eutectic, ReS2 can grow from rhenium (melting point at 3180 °C) and sulfur precursors in the temperature range of 460-900 °C with high efficiency.

Abstract2D magnetic materials have attracted intense attention as ideal platforms for constructing multifunctional electronic and spintronic devices. However, most of the reported 2D magnetic materials are mainly achieved by the mechanical exfoliation route. The direct synthesis of such materials is still rarely reported, especially toward thickness‐controlled synthesis down to the 2D limit. Herein, the thickness‐tunable synthesis of nanothick rhombohedral Cr2S3 flakes (from ≈1.9 nm to tens of nanometers) on a chemically inert mica substrate via a facile chemical vapor deposition route is demonstrated. This is accomplished by an accurate control of the feeding rate of the Cr precursor and the growth temperature. Furthermore, it is revealed that the conduction behavior of the nanothick Cr2S3 is variable with increasing thickness (from 2.6 to 4.8 nm and >7 nm) from p‐type to ambipolar and then to n‐type. Hereby, this work can shed light on the scalable synthesis, transport, and magnetic properties explorations of 2D magnetic materials.

As an anisotropic 2D layered material, rhenium disulfide (ReS) has attracted much attention because of its unusual properties and promising applications in electronic and optoelectronic devices. However, the low lattice symmetry and interlayer decoupling of ReS make asymmetric growth and out-of-plane growth occur quite easily; therefore, thick flake, dendritic and flower-like structures of ReS have mostly been obtained previously. Here, we report on an approach based on space-confined epitaxial growth for the controlled synthesis of ReS films. Using this approach, large-area and high-quality ReS films with uniform monolayer thickness can grow on a mica substrate. Furthermore, the weak van der Waals interaction between the surface of mica and ReS clusters, which favors surface-confined growth while avoiding out-of-plane growth, is critical for growing ReS with uniform monolayer thickness. The morphological evolution of ReS with the growth temperature reveals that asymmetric growth can be suppressed at relatively low temperatures. A ReS field-effect transistor displayed a current on/off ratio of 10 and an electron mobility of up to 40 cm V s, with outstanding photoresponsivity of 12 A W. This work not only promotes the large-scale employment of ReS in high-performance optoelectronic devices, but also provides a means of controlling the unusual growth behavior of low-lattice-symmetry 2D layered materials.

Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDCs) supply a versatile platform for investigating newfangled physical issues and developing potential applications in electronics/spintronics/electrocatalysis. Among these, NiTe 2 (a type-II Dirac semimetal) possesses a Dirac point near its Fermi level. However, as-prepared 2D MTMDCs are mostly environmentally unstable, and little attention has been paid to synthesizing such materials. Herein, a general chemical vapor deposition (CVD) approach has been designed to prepare thickness-tunable and large-domain (∼1.5 mm) 1T-NiTe 2 on an atomically flat mica substrate. Significantly, ultrahigh conductivity (∼1.15 × 10 6 S m −1 ) of CVD-synthesized 1T-NiTe 2 and high catalytic activity in pH-universal hydrogen evolution reaction have been uncovered. More interestingly, the 2D 1T-NiTe 2 maintains robust environmental stability for more than one year and even after a variety of harsh treatments. These results hereby fill an existing research gap in synthesizing environmentally stable 2D MTMDCs, making fundamental progress in developing 2D MTMDC-based devices/catalysts.

2D transition-metal dichalcogenides (TMDs) are an emerging class of materials with superior properties that make them highly attractive for fundamental studies of novel physics and for applications ranging from nanoelectronics and nanophotonics to sensing and catalysis. [1][2][3][4][5] As the most extensively Research on transition metal dichalcogenides (TMDs) has been accelerated by the development of large-scale synthesis based on chemical vapor deposition (CVD) growth. However, in most cases, CVD-grown TMDs are composed of randomly oriented grains, and thus contain many distorted grain boundaries (GBs), which seriously degrade their electrical and photoelectrical properties. Here, the epitaxial growth of highly aligned MoS 2 grains is reported on a twofold symmetry a-plane sapphire substrate. The obtained MoS 2 grains have an unusual rectangle shape with perfect orientation alignment along the [1-100] crystallographic direction of a-plane sapphire. It is found that the growth temperature plays a key role in its orientation alignment and morphology evolution, and high temperature is beneficial to the initial MoS 2 seeds rotate to the favorable orientation configurations. In addition, the photoluminescence quenching of the well-aligned MoS 2 grains indicates a strong MoS 2 −substrate interaction which induces the anisotropic growth of MoS 2 , and thus brings the formation of rectangle shape grains. Moreover, the well-aligned MoS 2 grains splice together without GB formation, and thus that has negligible effect on its electrical transport properties. The progress achieved in this work could promote the controlled synthesis of large-area TMDs single crystal film and the scalable fabrication of high-performance electronic devices.