Large-area MoS ₂ grown using H ₂ S as the sulphur source

Abstract

We report on the growth of molybdenum disulphide (MoS 2 ) using H 2 S as a gas-phase sulfur precursor that allows controlling the domain growth direction of domains in both vertical (perpendicular to the substrate plane) and horizontal (within the substrate plane), depending on the H 2 S:H 2 ratio in the reaction gas mixture and temperature at which they are introduced during growth. Optical and atomic force microscopy measurements on horizontal MoS 2 demonstrate the formation of monolayer triangular-shape domains that merge into a continuous film. Scanning transmission electron microscopy of monolayer MoS 2 shows a regular atomic structure with a hexagonal symmetry. Raman and photoluminescence spectra confirm the monolayer thickness of the material. Field-effect transistors fabricated on MoS 2 domains that are transferred onto Si/SiO 2 substrates show a mobility similar to previously reported exfoliated and chemical vapor deposition-grown materials.

Controlled growth of transition metal dichalcogenide monolayers using Knudsen-type effusion cells for the precursors

“…In comparison to the conventional TMD growth, where the precursors are placed freely in a reaction tube (see introduction), the amount of evaporated sulfur during a single growth cycle using our Knudsen cell is at least ∼1000 times lower [24,34]. Note that H 2 S was also reported as a precursor for the growth of good quality large area MoS 2 monolayer films, due to the fact that the flow rate of this gaseous precursor can be precisely controlled using mass flow controllers [35,36]. However, the maximum lateral sizes of the crystals grown by this method were limited to 10 μm [35,36].…”

“…Note that H 2 S was also reported as a precursor for the growth of good quality large area MoS 2 monolayer films, due to the fact that the flow rate of this gaseous precursor can be precisely controlled using mass flow controllers [35,36]. However, the maximum lateral sizes of the crystals grown by this method were limited to 10 μm [35,36]. The growth of MoS 2 from solid-state precursors of MoO 3 and S follows the following reaction steps.…”

High-quality synthetic 2D transition metal dichalcogenide semiconductors

“…In this respect sulphur can be easily replaced with H 2 S. The growth procedure results in highly-oriented vertically-aligned multilayers or horizontally-aligned monolayer domains in the shape of well-defined equilateral triangles (Fig. 2) [7]. At a high H 2 S/H 2 injection temperature of 700 °C with different H 2 S:H 2 ratios (5:15, 10:10 and 15:5 sccm), vertically-aligned multilayer MoS 2 domains with lengths of up to 10 μm have been observed.…”

Characteristics of layered tin disulfide deposited by atomic layer deposition with H2S annealing

“…Additionally, using highly reactive H 2 S gas produces a more favorable chemical reaction than sulfur powder when synthesizing 2D materials. 23 While ALD MoS 2 annealed with H 2 S gas was previously reported, 24 there have been no studies about post deposition annealing of SnS 2 with H 2 S gas. Thus, we carried out H 2 S gas annealing at various conditions and analyzed the physical and chemical characteristics with varying heat treatment conditions.…”