CVD controlled growth of large-scale WS<sub>2</sub> monolayers

Xu, Zhuhua; Lv, Yuguang; Li, Jingzhou; Huang, Feng; Nie, Pengbo; Zhang, Siwei; Zhao, Shichao; Zhao, Shunzheng; Wei, Guodan

doi:10.1039/c9ra06219j

Cited by 23 publications

(19 citation statements)

References 54 publications

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“…The advantage of WCl 6 compared to the powder-based method is much better scalability, and the advantage over the MOCVD films is the much shorter deposition time. FWHM values for films grown on sapphire substrates from a W(CO) 6 precursor range from 27 to 65 meV [27,34,[70][71][72], and span 21-68 meV when WO 3 powder is used as a precursor [7,20,23,[73][74][75]. Our FWHM value is an improvement on values (67 meV) reported by Park et al [26] who also employed gasphase CVD with a WCl 6 precursor.…”

Section: Resultssupporting

confidence: 49%

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

et al. 2022

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Monolayer tungsten disulphide (WS2) is a direct band gap semiconductor which holds promise for a wide range of optoelectronic applications. The large-area growth of WS2 has previously been successfully achieved using a W(CO)6 precursor, however, this is flammable and a potent source of carbon monoxide (CO) upon decomposition. To address this issue, we have developed a process for the wafer-scale growth of monolayer WS2 from a tungsten hexachloride (WCl6) precursor in a commercial cold-wall CVD reactor. In comparison to W(CO)6, WCl6 is less toxic and less reactive and so lends itself better to the large-scale CVD growth of 2D layers. We demonstrate that a post-growth H2S anneal can lead to a dramatic improvement in the optical quality of our films as confirmed by photoluminescence (PL) and Raman measurements. Optimised films exhibit PL exciton emission peaks with full width at half maximum of 51 ± 2 meV, comparable to other state-of-the-art methods. We demonstrate that our WS2 films can be readily transferred from the sapphire growth substrate to a Si/SiO2 target substrate with no detectable degradation in quality using a polystyrene support layer. Our approach represents a promising step towards the industrial-scale fabrication of p-n junctions, photodetectors and transistors based on monolayer WS2.

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Section: Resultssupporting

confidence: 49%

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

et al. 2022

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“…Various groups have investigated synthesis scalability by varying parameters, such as temperature, gas flow, environment (gas mixtures), pressure (low and atmospheric), catalyzer (sodium, terephthalic acid, etc. ), growth time, precursor amount and substrate cleaning [18][19][20][21][22][23][24][25][26][27][28][29][30]. These studies demonstrated divergent results even between similar growing conditions, leaving researchers puzzled about why this occurs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of WS2 by Chemical Vapor Deposition: Role of the Alumina Crucible

2022

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The role of the alumina crucible for the tungsten disulfide (WS2) growth on silicon dioxide substrates (SiO2/Si) under atmospheric pressure chemical vapor deposition (APCVD) was investigated. Both synthesis and properties of the APCVD-WS2 depend on the number of growth cycles when using the same alumina crucible. It was discovered that there is an ideal condition for the material’s synthesis, which is characterized by an increase in the photoluminescence (PL) yield and larger WS2 triangles. It usually happens for the first three growth cycles. For the fourth cycle and beyond, the PL decreases gradually. Simultaneously, atomic force microscopy images revealed no important changes in the topography of the WS2 flakes. As a function of the number of synthesis cycles, the progressive decrease in PL yield could be associated with materials with a higher density of defects, as identified by the LA(M)/A1g(M)−LA(M) ratio from Raman data using the green line.

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“…There are two peaks centred at 253 and 632 cm −1 , which are due to Cu 3 P [9,27]. The frequency difference between the two peaks is constant, unlike Van Der Waals two-dimensional materials, such as graphene, hexagonal boron nitride and molybdenum sulfide, of which the frequency difference is a function of the film thickness [28]. Therefore, the frequency difference cannot be utilized to determine the thickness of Cu 3 P film.…”

Section: Resultsmentioning

confidence: 99%

Chemical Vapor Deposition and Thermal Oxidation of Cuprous Phosphide Nanofilm

Peng

Zhao

2022

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Inorganic semiconductors usually show n-type characterization; the development of p-type inorganic semiconductor material will provide more opportunities for novel devices. In this paper, we investigated the chemical vapor deposition (CVD) of p-type cuprous phosphide (Cu3P) nanofilm and studied its thermal oxidation behavior. Cu3P film was characterized by optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), laser Raman spectroscopy (Raman), and fluorescence spectroscopy (PL). We found that the thickness of film ranged from 4 to 10 nm, and the film is unstable at temperatures higher than room temperature in air. We provide a way to prepare inorganic phosphide nanofilms. In addition, the possible thermal oxidation should be taken into consideration for practical application.

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CVD controlled growth of large-scale WS₂ monolayers

Abstract: Monolayer tungsten disulfide (WS2) with a direct band gap of ca. 2.0 eV and stable properties has been a hotspot in two-dimensional (2D) nanoelectronics and optoelectronics.

Cited by 23 publications

References 54 publications

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

Synthesis of WS2 by Chemical Vapor Deposition: Role of the Alumina Crucible

Chemical Vapor Deposition and Thermal Oxidation of Cuprous Phosphide Nanofilm

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CVD controlled growth of large-scale WS2 monolayers

Abstract: Monolayer tungsten disulfide (WS2) with a direct band gap of ca. 2.0 eV and stable properties has been a hotspot in two-dimensional (2D) nanoelectronics and optoelectronics.

Cited by 23 publications

References 54 publications

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

Optimisation of processing conditions during CVD growth of 2D WS2 films from a chloride precursor

Synthesis of WS2 by Chemical Vapor Deposition: Role of the Alumina Crucible

Chemical Vapor Deposition and Thermal Oxidation of Cuprous Phosphide Nanofilm

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CVD controlled growth of large-scale WS₂ monolayers