Synthesis of Ultrathin Metallic MTe2 (M = V, Nb, Ta) Single-Crystalline Nanoplates

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 MTe2 (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 MTe2 (M = V, Nb, Ta) nanoplates are high-quality single crystals. High-resolution scanning transmission electron microscope imaging reveals the VTe2 and NbTe2 nanoplates adopt the hexagonal 1T phase and the TaTe2 nanoplates show a monoclinic distorted 1T phase. Electronic transport studies show that MTe2 single crystals exhibit metallic behavior. Magnetic measurements show that VTe2 and NbTe2 exhibit ferromagnetism and TaTe2 shows paramagnetic behavior. The preparation of ultrathin few-layered MTe2 nanoplates will open up exciting opportunities for the burgeoning field of spintronics, sensors, and magneto-optoelectronics.