We report a general synthetic strategy for highly robust growth of diverse lateral heterostructures, multiheterostructures, and superlattices from two-dimensional (2D) atomic crystals. A reverse flow during the temperature-swing stage in the sequential vapor deposition growth process allowed us to cool the existing 2D crystals to prevent undesired thermal degradation and uncontrolled homogeneous nucleation, thus enabling highly robust block-by-block epitaxial growth. Raman and photoluminescence mapping studies showed that a wide range of 2D heterostructures (such as WS-WSe and WS-MoSe), multiheterostructures (such as WS-WSe-MoS and WS-MoSe-WSe), and superlattices (such as WS-WSe-WS-WSe-WS) were readily prepared with precisely controlled spatial modulation. Transmission electron microscope studies showed clear chemical modulation with atomically sharp interfaces. Electrical transport studies of WSe-WS lateral junctions showed well-defined diode characteristics with a rectification ratio up to 10.

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Two-dimensional materials with intrinsic magnetism have recently drawn intense interest for both the fundamental studies and potential technological applications. However, the studies to date have been largely limited to mechanically exfoliated materials. Herein, an atmospheric pressure chemical vapor deposition route to ultrathin group VB metal telluride MTe (M = V, Nb, Ta) nanoplates with thickness as thin as 3 nm is reported. It is shown that the resulting nanoplates can be systematically evolved from mostly thicker hexagonal domains to thinner triangular domains with an increasing flow rate of the carrier gas. X-ray diffraction and transmission electron microscopy studies reveal MTe (M = V, Nb, Ta) nanoplates are high-quality single crystals. High-resolution scanning transmission electron microscope imaging reveals the VTe and NbTe nanoplates adopt the hexagonal 1T phase and the TaTe nanoplates show a monoclinic distorted 1T phase. Electronic transport studies show that MTe single crystals exhibit metallic behavior. Magnetic measurements show that VTe and NbTe exhibit ferromagnetism and TaTe shows paramagnetic behavior. The preparation of ultrathin few-layered MTe nanoplates will open up exciting opportunities for the burgeoning field of spintronics, sensors, and magneto-optoelectronics.