Ultrahigh yield and large-scale fast growth of large-size high-quality van der Waals transition-metal telluride single crystals

Stable, rapid, and large-scale production of high-quality, large-size two-dimensional (2D) van der Waals single crystals is an important prerequisite for realizing the potential of highly integrated 2D devices. Here, we report a chloride-mediated chemical vapor transport (CVT) approach to achieve large-scale production of MoTe2 and WTe2 single crystals with lateral sizes up to 2 cm and extremely high quality. The largest magnetoresistance and carrier mobility can reach 170% and 1,390.09 cm2 V-1 s-1 for 2H-MoTe2 crystals and 506,017% and 11,952.10 cm2 V-1 s-1 for Td-WTe2 crystals, respectively, and all are among the best reported ones. Compared with the conventional CVT method, which has a long growth cycle and much reactive reagent surplus, the growth speed of the current method is about 73 to 9,144 times faster, with ultrahigh yields of nearly 100%. The high crystallinity guarantees the crystals can be easily exfoliated to large-scale 2D crystals down to monolayers for assembling 2D high-performance devices.