In
situ investigation of chemical vapor deposition (CVD) is of
critical importance to understanding growth mechanisms of transition-metal
dichalcogenides (TMDs) and to develop technologies for growing high-quality
monolayer single crystals. However, the in situ investigation is still
a great challenge in practice, because TMD CVD growth is conducted
at a high temperature with a reduction environment. In this work,
we developed an in situ investigation system for CVD growth and presented
real-time observations of monolayer MoS2 deposition on
the SiO2/Si substrate. We discovered that monolayer MoS2 should be grown via the vapor-state precursor reaction and
crystallized from the prenucleation sites on a substrate, an intermediate-phase
MoO2 was essential for the nucleation seeding, but the
population density should be controlled, and a high-concentration
S vapor promoted the in-plane epitaxial growth of MoS2;
hence, it was of great benefit to obtain a high-quality monolayer
with a compact shape.
Nano-thick 2D FAPbBr3 single-crystalline sheets were grown via a liquid-phase epitaxy method, and their optics and optoelectronic performances were revealed.
A Weyl semimetal is a novel crystal with low-energy electronic excitations that behave as Weyl fermions. It has received worldwide interest and was believed to have opened the next era of condensed matter physics after graphene and three-dimensional topological insulators. Howev-er, it is not easy to obtain a single large-size crystal because there are many nucleations in the preparation process. Here, a bottom-seed CVT growth method is proposed in this paper, and we acquired the large-size, high-quality NbAs single crystals up to 5x4x4 mm3 finally. X-ray diffrac-tion and STEM confirmed that they are tetragonal NbAs, which the key is to use seed crystal in vertical growth furnace. Notably, the photoelectric properties of the crystal are obtained under the existing conditions, which paves the way for the follow-up work.
A Weyl semimetal is a novel crystal with low-energy electronic excitations that behave as Weyl fermions. It has received worldwide interest and was believed to have introduced the next era of condensed matter physics after graphene and three-dimensional topological insulators. However, it is not easy to obtain a single large-sized crystal because there are many nucleations in the preparation process. A bottom-seed CVT growth method is proposed in this paper, and we acquired the large-sized, high-quality NbAs single crystals up to 4 × 3 × 3 mm3 finally. X-ray diffraction and STEM confirmed that they are tetragonal NbAs, which the key is to using the seed crystal in a vertical growth furnace. Notably, the photoelectric properties of the crystal are obtained under the existing conditions, which paves the way for follow-up work.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.