Two-dimensional (2D) vertical heterojunctions (HSs), which are usually fabricated by vertically stacking two layers of transition metal dichalcogenide (TMDC), have been intensively researched during the past years. However, it is still an enormous challenge to achieve controllable preparation of the TMDC trilayer or multilayered van der Waals (vdWs) HSs, which have important effects on physical properties and device performance. In this review, we will introduce fundamental features and various fabrication methods of diverse TMDC-based multilayered vdWs HSs. This review focuses on four fabrication methods of TMDC-based multilayered vdWs HSs, such as exfoliation, chemical vapor deposition (CVD), metal-organic chemical vapor deposition (MOCVD), and pulsed laser deposition (PLD). The latest progress in vdWs HS-related novel physical phenomena are summarized, including interlayer excitons, long photocarrier lifetimes, upconversion photoluminescence, and improved photoelectrochemical catalysis. At last, current challenges and prospects in this research field are provided.

Atomically thin transition metal dichalcogenides (TMDCs) have attracted worldwide interest for their prospective potential in electronic and optoelectronic fields. However, TMDCs tend to grow into two-dimensional (2D) flakes rather than one-dimensional (1D) micro/ nanoribbons due to their intrinsic layered structure. Here, large-scale bilayer WS 2 ribbons with unusual shapes have been achieved through the space-confined chemical vapor deposition method via utilizing WO 3 and S powders as the precursors. The microstructures and optical and electronic properties of as-grown bilayer WS 2 ribbons have been systematically researched. Moreover, the possible growth mechanism of such special structures is revealed by the growth-time-dependent morphological evolution of the WS 2 crystals. Our results emphasize the prospects for the successful fabrication of novel 1D TMDC structures for high-performance optoelectronic devices at nanoscale, including transistors, photocatalysts, photovoltaic cells, and spintronic devices.

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The controllable fabrication of high-yield and largesized atomically thin MoS 2 dendritic flakes is highly desirable for catalytic applications due to the abundant edge sites. Here, we present the synthesis of high-yield monolayer MoS 2 dendritic flakes with serrated edges on a whole amorphous Si/SiO 2 substrate by utilizing an ambient-pressure space-confined chemical vapor deposition (CVD) method. The two-dimensional (2D) monolayer MoS 2 flakes were shown to exhibit a remarkable shape evolution from triangular flakes to dendritic flakes with serrated edges to triangular flakes with a few short branches, as well as size variations ranging from several micrometers to ∼855 μm, by tailoring the growth parameters. Optical and electrical characterizations proved the formation of grain boundaries in the dendritic flake obtained at high growth temperatures. Moreover, the growth mechanism of 2D MoS 2 flakes was discussed based on the morphological evolution of 2D domains under diverse growth parameters. Our study paves a novel pathway to optimize the fabrication of 2D dendritic flakes and provides technical guidance for designing effective catalysts.