Controllable Water Vapor Assisted Chemical Vapor Transport Synthesis of WS₂–MoS₂ Heterostructure

Abstract

The vapor phase synthesis of two-dimensional transition-metal dichalcogenides (MX2) and their heterostructures is often poorly reproducible and sensitive to uncontrolled environmental humidity. It was recently realized that water vapor can play important roles in the growth of MX2 by reacting with MX2 at high temperature to form volatile metal oxyhydroxide (MOx(OH)y) and hydrogen chalcogenides (H2X) that dramatically change the growth processes. Here we report the controllable synthesis of WS2, MoS2, and their heterostructures using water-assisted chemical vapor transport (CVT). The water vapor can be tunably delivered by thermal dehydration of calcium sulfate dihydrate (CaSO4‧2H2O) solid precursor, which not only provides much lower vapor pressure baseline and a wider tunable range than liquid water, but also can be readily integrated into a chemical vapor deposition process. This allows controlled growth of monolayer,

Two-Dimensional Platinum Diselenide: Synthesis, Emerging Applications, and Future Challenges

“…As a widely studied traditional crystal growth method, CVT has also been employed to direct synthesize 2D semiconductor materials, such as TiSe 2 , MoS 2 , WS 2 , and ReS 2 [ 137 – 141 ]. Benefitting from the good controllability of the growth parameters, the properties, structure, and composition of 2D materials can be well regulated.…”

Triple sum frequency pump-probe spectroscopy of transition metal dichalcogenides

“…[45] Note that this exact MoS 2 thin film sample was previously explored in Morrow et al [27]. Following the methods detailed in Zhao and Jin [69], WS 2 (MoS 2 ) nanostructure samples on 300 nm SiO 2 /Si substrates were prepared using water vapor assisted chemical vapor transport growth by heating 100 mg WS 2 (MoS 2 ) powder to 1200 • C at 800 torr in a tube furnace in which water vapor was produced by heating 1 g CaSO 4 ·2H 2 O powder to 150 • C (120 • C) using heating tape wrapped around the tube furnace. 100 sccm argon was used as the carrier gas during the reaction.…”

Epitaxial Growth and Determination of Band Alignment of Bi2Te3–WSe2 Vertical van der Waals Heterojunctions

“…TI is historically well-known for their widespread uses in thermoelectric in tandem with the increasing important topological insulating properties induced by the quantum spin-Hall effect. [20][21][22] Bi-based TIs are characterized by the quintuple layered (QL) structure that comprises a sequential stacking of covalently bonded 2D units made of Te/Se (1)-Bi-Te/Se (2)-Bi-Te/Se (1),…”

“…where (1) and (2) denote the different chemical state of anions. 23 Among them, Bi2Te3 has recently gained immense interest by virtue of its structural stability, earth abundance, and high carrier mobility.…”