Judicious Selection of Precursors with Suitable Chemical Valence State for Controlled Growth of Transition Metal Chalcogenides

Lan, Shangui; Zhang, Zhixiang; Hong, Yukun; She, Yihong; Pan, Baojun; Xu, Yang; Wang, Peijian

doi:10.1002/admi.202300713

Cited by 3 publications

(1 citation statement)

References 75 publications

(86 reference statements)

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“…Generally, powdered WO 3 is the most widely used precursor, along with various W-based carbonates, hexachlorides, and oxychlorides [26,27] (for metal-organic CVD). To accomplish synthesis in a 2D form, the conventional CVD method uses the vapor-solidsolid (VSS) mechanism based on WO 3 adsorption on the substrate and corresponding chemical reactions facilitated through surface chalcogenide diffusion [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Metatungstate Chemical Vapor Deposition of WSe2: Substrate Effects, Shapes, and Morphologies

Buchkov,

Rafailov,

Minev

et al. 2024

Crystals

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Owing to their exceptional properties, which are usually determined by the growth conditions, 2D transition metal dichalcogenides (TMDCs) offer numerous research directions for applications in the fields of spintronics, valleytronics, and optoelectronics. Here, we focus on the chemical vapor deposition (CVD) synthesis of WSe2 (tungsten diselenide) nanoclusters/nanoflakes by using a liquid precursor for tungsten (ammonium metatungstate) on Si/SiO2, fused silica, and sapphire substrates. Various WSe2 clusters with different sizes, thicknesses, and geometries were analyzed by means of optical and atomic force microscopy (AFM) and Raman spectroscopy. The observed structures were mostly WSe2 multilayers; however, monolayer formations were also found. They showed significant morphological differences, as well as wide nucleation density and size variations, possibly related to precursor/substrate surface interactions under the same CVD synthesis conditions. The largest WSe2 domains with a lateral size of up to hundreds of micrometers were observed on sapphire, probably caused by a higher growth rate of singular nucleation sites. WSe2 domains with irregular and triangular shapes were simultaneously identified on fused silica, whereas multilayered pyramidal WSe2 structures dominated in the case of Si/SiO2 substrates. The application of polarized Raman spectroscopy to precisely determine and differentiate the characteristic vibrational modes (A1g, E2g, and 2LA(M)) enabled the unambiguous identification of 2D and/or multilayered WSe2 formations with a high crystallinity level. The presented comparative analysis of samples prepared in relatively simple synthesis conditions (moderate working temperatures and ambient pressure) provides a base for further progress of the facile metatungstate CVD method and relevant opportunities for the exploration of 2D TMDC materials.

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Section: Introductionmentioning

confidence: 99%

Metatungstate Chemical Vapor Deposition of WSe2: Substrate Effects, Shapes, and Morphologies

Buchkov,

Rafailov,

Minev

et al. 2024

Crystals

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Low‐temperature chemical vapor deposition growth of 2D materials

Lei,

Wang,

et al. 2024

Electron

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Two‐dimensional (2D) materials have atomic thickness, and thickness‐dependent electronic transport, optical and thermal properties, highlighting great promise applications in future semiconductor devices. Chemical vapor deposition (CVD) is considered as an industry‐oriented method for macro‐synthesis of 2D materials. In conventional CVD, high temperatures are required for the synthesis of high‐quality large‐size 2D materials, which is incompatible with of back‐end‐of‐line of the complementary metal oxide semiconductor (CMOS) techniques. Therefore, low‐temperature synthesis of 2D materials is of critical importance for the advancement toward practical applications of 2D materials with the CMOS technologies. In this review, we focus on strategies for the low‐temperature growth of 2D materials, including the use of low‐melting‐point precursors, metal‐organic CVD, plasma‐enhanced CVD, van der Waals‐substrate vapor phase epitaxy, tellurium‐assisted CVD, salt‐assisted CVD, etc., with discussions of their reaction mechanisms, applications, associated advantages, and limitations. We also provide an outlook and perspectives of future low‐temperature chemical vapor deposition growth of 2D materials.

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Theoretical study on the nucleation control of WS2 on Au(111) surfaces

Hu,

Yuan

2024

Acta Phys. Sin.

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Two-dimensional tungsten disulfide (WS2), as a semiconductor material with layer-dependent electronic and optoelectronic properties, has garnered significant attention for its application prospects in the field of optoelectronic devices. Currently, the production of wafer-scale monolayer WS2 films stands as a pivotal challenge that must be overcome to harness its potential in advanced transistors and integrated circuits. Chemical vapor deposition (CVD) has emerged as a viable technique for fabricating large-scale, high-quality monolayer WS2 films, yet the intricate and subtle growth process often results in low efficiency and variable quality. To steer experimental endeavors toward minimizing grain boundaries in WS2 and augmenting film quality for enhanced electronic performance and mechanical stability, this study investigates the nucleation mechanisms of the CVD growth of WS2 based on first-principles theoretical calculations. By incorporating the chemical potential as a key variable, we have analyzed the growth energy curves of WS2 under diverse experimental conditions. Our findings demonstrate that modulating the temperature or pressure of tungsten and sulfur precursors can decisively influence the nucleation rate of WS2. Specifically, the nucleation rate peaks at a tungsten source temperature of 1250 K, while an increase in sulfur source temperature or a decrease in pressure can suppress the nucleation rate, thereby enhancing the crystallinity and uniformity of the monolayer WS2. These insights not only furnish a robust theoretical foundation for experimentally fine-tuning the nucleation rate as needed but also provide strategic guidance for optimizing experimental parameters to refine the crystallinity and uniformity of monolayer WS2 films. Such advancements are anticipated to accelerate the deployment of WS2 materials in a spectrum of high-performance electronic devices, marking a significant stride in material science and industrial applications.

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Judicious Selection of Precursors with Suitable Chemical Valence State for Controlled Growth of Transition Metal Chalcogenides

Cited by 3 publications

References 75 publications

Metatungstate Chemical Vapor Deposition of WSe2: Substrate Effects, Shapes, and Morphologies

Metatungstate Chemical Vapor Deposition of WSe2: Substrate Effects, Shapes, and Morphologies

Low‐temperature chemical vapor deposition growth of 2D materials

Theoretical study on the nucleation control of WS<sub>2 </sub>on Au(111) surfaces

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