posted on 2021-08-10, 18:42authored byLiang Ma, Juntong Zhu, Wei Li, Rong Huang, Xiangyi Wang, Jun Guo, Jin-Ho Choi, Yanhui Lou, Dan Wang, Guifu Zou
Molybdenum ditelluride (MoTe2) has attracted ever-growing
attention in recent years due to its novel characteristics in spintronics
and phase-engineering, and an efficient and convenient method to achieve
large-area high-quality film is an essential step toward electronic
applications. However, the growth of large-area monolayer MoTe2 is challenging. Here, for the first time, we achieve the
growth of a centimeter-sized monoclinic MoTe2 monolayer
and manifest the mechanism of immobilized precursor particle driven
growth. Microscopic characterizations reveal an obvious trend of immobilized
precursor particles being consumed by the monolayer and continuing
to provide a source for the growth of the monolayer. Time-of-flight
secondary ion mass spectrometry verifies the attachment of hydroxide
ions on the surface of the MoTe2 monolayer, thereby realizing
the inhibition of crystal growth along the [001] zone axis and the
continuous growth of the MoTe2 monolayer. The first-principles
DFT calculations prove the mechanism of immobilized precursor particles
and the absorption of hydroxide ions on the MoTe2 monolayer.
The as-grown MoTe2 monolayer exhibits a surface roughness
of 0.19 nm and average conductivity of 1.5 × 10–5 S/m, which prove the smoothness and uniformity of the MoTe2 monolayer. Temperature-dependent electrical measurements together
with the transfer characteristic curves further demonstrate the typical
semimetallic properties of monoclinic MoTe2. Our research
elaborates the microscopic process of immobilized precursor particles
to grow large-area MoTe2 monolayer and provides a new thinking
about the growth of many other two-dimensional materials.