  Recently, new states of matter like superconducting or topological quantum
states were found in transition metal dichalcogenides (TMDs) and manifested
themselves in a series of exotic physical behaviors. Such phenomena have been
demonstrated to exist in a series of transition metal tellurides including
MoTe2, WTe2 and alloyed MoxW1-xTe2. However, the behaviors in the alloy system
have been rarely addressed due to their difficulty in obtaining atomic layers
with controlled composition, albeit the alloy offers a great platform to tune
the quantum states. Here, we report a facile CVD method to synthesize the
MoxW1-xTe2 with controllable thickness and chemical composition ratios. The
atomic structure of monolayer MoxW1-xTe2 alloy was experimentally confirmed by
scanning transmission electron microscopy (STEM). Importantly, two different
transport behaviors including superconducting and Weyl semimetal (WSM) states
were observed in Mo-rich Mo0.8W0.2Te2 and W-rich Mo0.2W0.8Te2 samples
respectively. Our results show that the electrical properties of MoxW1-xTe2 can
be tuned by controlling the chemical composition, demonstrating our
controllable CVD growth method is an efficient strategy to manipulate the
physical properties of TMDCs. Meanwhile, it provides a perspective on further
comprehension and shed light on the design of device with topological
multicomponent TMDCs materials.
