CVD controlled preparation and growth mechanism of 2H-WS2 nanosheets

Yan, Jiashuo; Lian, Shuang; Cao, Zhigang; Du, Yadan; Sun, Hongwen; An, Yukai

doi:10.1016/j.vacuum.2022.111564

Cited by 12 publications

(9 citation statements)

References 37 publications

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“…The calculated values of the lattice constants are a=3.154, b=3.154 Å, and c=12.362 Å. The lattice values match the previously reported data [42,43] …”

Section: Resultssupporting

confidence: 87%

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Enhanced Photoelectrochemical Activity Realized from WS₂ Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

Ladhane,

Shah,

Shinde

et al. 2024

ChemElectroChem

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We report the synthesis of tungsten sulfide (WS2) films using RF‐magnetron sputtering at different RF powers. X‐ray diffraction (XRD) data confirm the hexagonal crystal structure of WS2 with an average crystallite size of ∼44.54 Å. With increased RF power, the preferred orientation of WS2 crystallites shifts from (002) to (100). Linear sweep voltammetry (LSV) was used to assess the Photoelectrochemical (PEC) activity of WS2 films. The film deposited at 150 W demonstrated the highest photocurrent density of 5.44 mA/cm2. The 150 W film also showed a lower Tafel slope of ∼0.374 V/decade, indicating superior PEC activity. Mott Schottky's (MS) analysis revealed a notable shift in the flat band potential towards the negative side, suggesting a shifting of the Fermi level towards the conduction band. WS2 film grown at 150 W demonstrated a majority charge carrier density of 6.2×1021 cm−3 and a depletion layer width of 1.54 nm. The observed low charge transfer resistance of 155 Ω contributed to the enhanced PEC activity with a relaxation time constant of 37 ms. These properties suggest that WS2 can be suitable for PEC water splitting.

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“…The calculated values of the lattice constants are a=3.154, b=3.154 Å, and c=12.362 Å. The lattice values match the previously reported data [42,43] …”

Section: Resultssupporting

confidence: 87%

“…The lattice values match the previously reported data. [42,43] The peak's full width at half maximum (FWHM) is inversely proportional to the crystallite size (D hkl ) of the crystallites. It can be calculated by applying the Debye-Scherrer formula, [44]…”

Section: X-ray Diffraction Analysismentioning

confidence: 99%

Enhanced Photoelectrochemical Activity Realized from WS₂ Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

Ladhane,

Shah,

Shinde

et al. 2024

ChemElectroChem

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“…We employed a constant flow in a quartz tube to retain the precursor to establish a stable air flow environment, which guarantees that the WS 2 vapor is thoroughly volatilized and evenly dispersed throughout the reaction process. As a result, the concentration distribution of WS 2 precursors (volatilization and diffusion) may be regarded as the primary factor influencing the various form morphologies (Yan et al, 2023).…”

Section: Resultsmentioning

confidence: 99%

PVD growth of spiral pyramid-shaped WS2 on SiO2/Si driven by screw dislocations

et al. 2023

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Atomically thin layered transition metal dichalcogenides (TMDs), such as MoS2 and WS2, have been getting much attention recently due to their interesting electronic and optoelectronic properties. Especially, spiral TMDs provide a variety of candidates for examining the light-matter interaction resulting from the broken inversion symmetry, as well as the potential new utilization in functional optoelectronic, electromagnetic and nanoelectronics devices. To realize their potential device applications, it is desirable to achieve controlled growth of these layered nanomaterials with a tunable stacking. Here, we demonstrate the Physical Vapor Deposition (PVD) growth of spiral pyramid-shaped WS2 with ∼200 μm in size and the interesting optical properties via AFM and Raman spectroscopy. By controlling the precursors concentration and changing the initial nucleation rates in PVD growth, WS2 in different nanoarchitectures can be obtained. We discuss the growth mechanism for these spiral-patterned WS2 nanostructures based on the screw dislocations. This study provides a simple, scalable approach of screw dislocation-driven (SDD) growth of distinct TMD nanostructures with varying morphologies, and stacking.

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“…To attain this objective, it is customary to employ elevated temperatures to guarantee an adequate source supply and a high rate of atomic surface diffusion [26][27][28][29] However, achieving TMDs with optimal characteristics necessitates precise control of growth parameters. Temperature, for instance, is a fundamental factor influencing growth kinetics and crystal structure, with specific temperature ranges tailored to different TMDs facilitating precursor diffusion and enhancing crystalline quality [30,31] Precursor flow rate governs the supply of source materials, impacting growth kinetics and thickness uniformity. It is crucial to maintain an optimal flow rate to avoid excessive precursor decomposition or limited source availability, ensuring controlled growth and the required thickness [18,24,25]Additionally, growth time significantly affects the extent of TMD formation and crystal size, with longer durations promoting complete precursor conversion and yielding larger crystals.…”

Section: Introductionmentioning

confidence: 99%

“…However, extended growth times may also introduce defects and impurities, necessitating a balance between growth duration and material quality [13,14]. The amount of material utilized in the growth process is crucial in ascertaining the dimensions and thickness of TMDs materials [16,32]. Precursor concentration directly affects the nucleation density and growth rates, with higher concentrations leading to denser nucleation and faster growth, resulting in larger and thicker TMD crystals.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Fundamental Conditions for Growth to Obtain High-Quality WS2 Using a Process of physical vapor deposition

Madoune

Zhang

Ismail

2023

Preprint

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Two-dimensional layered transition-metal dichalcogenides (2D-TMDs) have garnered significant attention due to their layer number-dependent electronic properties, making them promising candidates for atomically thin electronics and optoelectronics. However, current research has primarily focused on exfoliated TMD materials, which have limitations in size, layer number control, and yield. Therefore, a crucial challenge remains in producing large-sized TMD single crystals with precise control over the layer number. A comprehensive understanding and precise control of the growth conditions are imperative to address this challenge. This study systematically investigated key growth conditions, including temperature, precursor flow, growth duration, material quantity, gas flow, and slide position. By optimizing these parameters, we successfully synthesized TMD materials with an impressive size of 850 µm. Notably, we achieved the preparation of monolayer WS2 single crystals on a large scale within a remarkably short duration of 10 minutes, exhibiting a lateral growth rate of up to 1.4 μm/s, which is comparable to the best-exfoliated monolayers. The findings from our study provide a robust pathway for the rapid growth of high-quality TMD single crystals, facilitating further advancements in this field.

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CVD controlled preparation and growth mechanism of 2H-WS2 nanosheets

Cited by 12 publications

References 37 publications

Enhanced Photoelectrochemical Activity Realized from WS₂ Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

Enhanced Photoelectrochemical Activity Realized from WS₂ Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

PVD growth of spiral pyramid-shaped WS2 on SiO2/Si driven by screw dislocations

Investigating the Fundamental Conditions for Growth to Obtain High-Quality WS2 Using a Process of physical vapor deposition

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CVD controlled preparation and growth mechanism of 2H-WS2 nanosheets

Cited by 12 publications

References 37 publications

Enhanced Photoelectrochemical Activity Realized from WS2 Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

Enhanced Photoelectrochemical Activity Realized from WS2 Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

PVD growth of spiral pyramid-shaped WS2 on SiO2/Si driven by screw dislocations

Investigating the Fundamental Conditions for Growth to Obtain High-Quality WS2 Using a Process of physical vapor deposition

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Enhanced Photoelectrochemical Activity Realized from WS₂ Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting

Enhanced Photoelectrochemical Activity Realized from WS₂ Thin Films Prepared by RF‐Magnetron Sputtering for Water Splitting