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

Tang, Lei; Tan, Jing; Nong, Huiyu; Liu, Bilu; Cheng, Hui‐Ming

doi:10.1021/accountsmr.0c00063

Cited by 158 publications

(116 citation statements)

References 51 publications

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“…In particular, CVD using vapours from S and MoO 3 powders has been widely explored by several research groups, since it is a cost-effective method to produce MoS 2 domains with good crystalline quality on different substrates [31][32][33]. Although monolayer flakes with a triangular or hexagonal shape and lateral extension from tens to hundreds of micrometres have been obtained under optimized CVD conditions [34], achieving coverage and thickness uniformity on the wafer scale still represents a huge challenge, due to the difficulty of controlling all the parameters involved in the process (including the substrate temperature, the evaporation rates of the S and Mo precursors, the pressure in the chamber, and the carrier gas flow rate) [35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS2 Obtained by MoO3 Sulfurization

et al. 2022

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In this paper, we report a multiscale investigation of the compositional, morphological, structural, electrical, and optical emission properties of 2H-MoS2 obtained by sulfurization at 800 °C of very thin MoO3 films (with thickness ranging from ~2.8 nm to ~4.2 nm) on a SiO2/Si substrate. XPS analyses confirmed that the sulfurization was very effective in the reduction of the oxide to MoS2, with only a small percentage of residual MoO3 present in the final film. High-resolution TEM/STEM analyses revealed the formation of few (i.e., 2–3 layers) of MoS2 nearly aligned with the SiO2 surface in the case of the thinnest (~2.8 nm) MoO3 film, whereas multilayers of MoS2 partially standing up with respect to the substrate were observed for the ~4.2 nm one. Such different configurations indicate the prevalence of different mechanisms (i.e., vapour-solid surface reaction or S diffusion within the film) as a function of the thickness. The uniform thickness distribution of the few-layer and multilayer MoS2 was confirmed by Raman mapping. Furthermore, the correlative plot of the characteristic A1g-E2g Raman modes revealed a compressive strain (ε ≈ −0.78 ± 0.18%) and the coexistence of n- and p-type doped areas in the few-layer MoS2 on SiO2, where the p-type doping is probably due to the presence of residual MoO3. Nanoscale resolution current mapping by C-AFM showed local inhomogeneities in the conductivity of the few-layer MoS2, which are well correlated to the lateral changes in the strain detected by Raman. Finally, characteristic spectroscopic signatures of the defects/disorder in MoS2 films produced by sulfurization were identified by a comparative analysis of Raman and photoluminescence (PL) spectra with CVD grown MoS2 flakes.

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Section: Introductionmentioning

confidence: 99%

Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS2 Obtained by MoO3 Sulfurization

et al. 2022

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“…CVD method, as one of the most promising approaches to synthesize large-scale and high-quality 2D materials, [48][49][50] has been widely applied in preparing different types of vdW heterostructures. Compared to mechanical stacking method, CVD could generate large-area heterostructures with fewer interlayer contaminations and stronger interlayer coupling.…”

Section: The Synthesis Methods Of Vdw Heterostructuresmentioning

confidence: 99%

Recent Advances on Tuning the Interlayer Coupling and Properties in van der Waals Heterostructures

Chen

Yang

et al. 2022

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Abstract2D van der Waals (vdW) heterostructures are receiving increasing research attention due to the theoretically amazing properties and unprecedented application potential. However, the as‐synthesized heterostructures are generally underperforming due to the weak interlayer coupling, which inspires the researchers to find ways to modulate the interlayer coupling and properties, realizing the tailored performance for actual applications. There have been a lot of publications regarding the controllable regulation of the structures and properties of 2D vdW heterostructures in the past few years, while a review work summarizing the current advances is not yet available, though it is significant. This paper conducts a state‐of‐the‐art review regarding the current research progress of performance modulation of vdW heterostructures by different techniques. First, the general synthesis methods of vdW heterostructures are summarized. Then, different performance modulation techniques, that is, mechanical‐based, external fields‐assisted, and particle beam irradiation‐based methods, are discussed and compared in detail. Some of the newly proposed concepts are described. Thereafter, applications of vdW heterostructures with tailored properties are reviewed for the application prospects of the topic around this area. Moreover, the future research challenges and prospects are discussed, aiming at triggering more research interest and device applications around this topic.

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“…One factor that influences the uniformity of the layer number largely is the uniformity of the precursor feeding. [206][207][208] In the conventional powder CVD, it is a "point-to face" metal-source supply with the metal oxides precursors placed in the upstream, or below the substrate. [209] It is extremely hard to control the uniformity because the inhomogeneous release rates of the metal precursor in different direction and low repeatability due to the time-to-time difference.…”

Section: Layer Numbermentioning

confidence: 99%

Toward Wafer‐Scale Production of 2D Transition Metal Chalcogenides

Wang

Yang

2021

Adv Elect Materials

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When the timeline reached 2004, graphene, the single layer of graphite, was discovered through a scotch-tape exfoliation method and was found to have ultrahigh mobility. [25][26][27] Various 2D materials such as transition metal chalcogenides (TMCs), [28][29][30] boron nitrides (BNs), [31,32] black phosphorus, [33,34] and some new materials including Si, [35] Te, [36] and black arsenic-phosphorus [37] were subsequently synthesized, enabling the fabrication of numerous novel devices. The field of 2D materials is now making strong voice, which is no longer ignored by the scientific and technological community. [38][39][40] Among the various 2D materials, the TMCs constituted by the transition metal elements (M) and the chalcogen elements (X) are a large family. M can range from group 4B to group 10 in the periodic table, while X is S, Se, or Te. [41][42][43][44][45][46][47] Figure 1a exhibits the binary TMCs that have already been explored. This variation of composition of elements transfers to a wide range of properties ranging from insulators (e.g., HfS 2 ), [48,49] semiconductors (e.g., MoS 2 , WS 2 ), [50,51] semimetals (e.g., MoTe 2 , TiSe 2 ), [52,53] to metals (e.g., NbSe 2 , VS 2 ). [54][55][56] Furthermore, TMCs can form alloys in the formula such as WSe 2−x S x , with composition-tunable properties. [57][58][59] Unlike semimetallic graphene, semiconducting TMCs usually possess a bandgap. For example, MoS 2 exhibits a bandgap, transitioning from indirect bandgap to direct bandgap when it thins from bulk phase to monolayer (Figure 1b), boosting the photoluminescence (PL) efficiency. [51,[60][61][62] Additionally, inversion symmetry breaking and large spin-orbit interaction, resulting in two energetic degenerate but inequivalent valleys in the band structure of a TMC (Figure 1c), may lead to breakthroughs in valleytronics and spintronics. [63][64][65][66][67][68][69][70] A few TMCs (e.g., NbSe 2 , TaS 2 , VSe 2 ) have shown superconductivity, [71,72] charge density wave [73,74] and Mott transition (transition from metal to nonmetal). [75,76] In addition, some novel TMCs such as Fe 3 GeTe 2 display intrinsic magnetism with gate-tunable Curie points. [66,77] Semimetallic TMCs like WTe 2 show topological structures in the energy band, enabling the study on topological physics. [78,79] The rich intrinsic properties and superior tunability of TMCs hold great promise for all kinds of technologically important applications in electronics, optoelectronics, spintronics, valleytronics, etc. (Figure 1d). [51,[80][81][82][83][84][85][86][87][88][89][90][91] Due to numerous unique properties of 2D TMCs, devices such as transistors, photodetectors (PDs), and photodiodes based on 2D TMCs have been actively pursued. The ultimate destination of the miniaturization of the electronic devices will 2D transition metal chalcogenides (TMCs) have attracted tremendous interest from both the scientific and technological communities due to their variety of properties and superior tunability through layer number, composition, and inter...

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

Cited by 158 publications

References 51 publications

Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS2 Obtained by MoO3 Sulfurization

Multiscale Investigation of the Structural, Electrical and Photoluminescence Properties of MoS2 Obtained by MoO3 Sulfurization

Recent Advances on Tuning the Interlayer Coupling and Properties in van der Waals Heterostructures

Toward Wafer‐Scale Production of 2D Transition Metal Chalcogenides

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