Oxide Inhibitor-Assisted Growth of Single-Layer Molybdenum Dichalcogenides (MoX₂, X = S, Se, Te) with Controllable Molybdenum Release

Abstract

Though chemical vapor deposition (CVD) methods have been widely used in the growth of two-dimensional transition-metal dichalcogenides (2D TMDCs), the controllable fabrication of 2D TMDCs is yet hard to achieve because of the great challenge of concisely controlling the release of precursors vapor, one of the most critical growth kinetic factors. To solve this important issue, here we report the utilization of oxide inhibitors covering Mo source during CVD reactions to manipulate the release of Mo vapor. In contrast to the lack of capability of conventional CVD methods, 2D molybdenum dichalcogenide (MoX2, X = S, Se, Te) monolayers were successfully fabricated through the proposed CVD protocol with the oxide-inhibitor-assisted growth (OIAG) strategy. In this way, despite the fact that only separated MoTe2 flakes were prepared, both MoS2 (continuous and clean) and MoSe2 (continuous but dotted) monolayer films at the scale of centimeter were obtained. The presented OIAG method enables a comprehensive understanding and precise control of the reaction kinetics for improved growth of 2D MoX2.

Selective Area Growth and Transfer of High Optical Quality MoS2 Layers

“…One of the major drawbacks in a conventional MO‐based CVD growth is the presence of excessive nucleation density, which causes the formation of MO entities prior to their sulfurization, [ 19 ] and thus multilayer and other inhomogeneities are obtained. Several approaches were suggested in order to control the metal precursor concentration and to avoid this unwanted outcome, including the use of a separate quartz tubes for the MO and chalcogen precursors, [ 26 ] the use of the so‐called seed promoters, [ 23,27 ] or the use of physical barriers, [ 28–33 ] to diminish the amount of metal precursor on the growth substrate, and thus reducing by that the nucleation density and inhibiting the formation of MO nanostructures prior to their sulfurization. The use of a confined space [ 28–32,34 ] to grow a TMDC layer is a particular case of the latter.…”

2D Ultrawide Bandgap Semiconductors: Odyssey and Challenges

“…[177] In this regard, CVD provides a controllable and scalable pathway to grow large-size and single-crystalline 2D materials at a reasonable cost. [70,[178][179][180][181][182][183] In the last three years, there have been breakthrough achievements in the CVD growth of 2D UWBG materials. For instance, a pioneering research of growing waferscale single-crystal h-BN film via self-collimated grain formation was reported by Kim's group.…”

Chemical Vapor Deposition Growth of Two-Dimensional Compound Materials: Controllability, Material Quality, and Growth Mechanism

“…In this regard, we prepared 2D In2Se3 in a confined microreactor made up of two face-to-face stacked mica substrates. 10 Because of the well-controlled precursor concentration, the as-prepared In2Se3 reached a size of over 200 µm. In addition, the development of new growth reactors that moderate the gas flow is a promising way to grow other 2D compounds.…”