Secondary granulation-assisted CVD growth of WS2, TiS2 and NbS2 crystals

2021 ◽  
pp. 2151029
Author(s):  
Ning Li ◽  
Ming Liu ◽  
Qing Chang ◽  
Huiqi Wang ◽  
Chaorui Xue ◽  
...  
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Domain Size ◽  
Cost Effective ◽  
Nucleation Density ◽  
Practical Applications ◽  
Transmission Electron ◽  
Metal Precursors ◽  
Metal Dichalcogenides ◽  
Cvd Growth

Chemical vapor deposition (CVD) is a cost-effective and scalable approach to prepare high-quality two-dimensional (2D) transition metal dichalcogenides (TMDCs), which is crucial for practical applications. Nevertheless, how to sublimate metal precursors with high melting point efficiently is still challenging. Herein, we demonstrate a novel secondary granulation-assisted route to adjust the supply of WO3 at moderate temperature (730 [Formula: see text]C), guarantee the appropriate tungsten/chalcogen ratio, and then achieve the controllable growth of monolayer WS2 crystals. Transmission electron microscopy, Raman and other characterizations indicate their high crystallinity. Notably, the domain size, nucleation density and morphology can be regulated by the size of the granulated WO3 particles. Moreover, the related mechanism is explained in detail, which applies equally to the steerable growth of TiS2 and NbS2, confirming the versatility of this method for growing 2D TMDCs. Therefore, this work offers a facile route for the microthermal CVD growth of 2D TMDCs crystals and drives the development of applications.

scholarly journals Overview of Rational Design of Binary Alloy for the Synthesis of Two-Dimensional Materials

Surfaces ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 26-39
Author(s):  
Hongyan Zhu ◽  
Chao Zhang ◽  
Xuefu Zhang ◽  
Zhiyuan Shi ◽  
Tianru Wu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Rational Design ◽  
Hexagonal Boron Nitride ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Domain Size ◽  
Two Dimensional ◽  
Practical Applications ◽  
Metal Catalyzed

Two-dimensional (2D) materials attracted widespread interest as unique and novel properties different from their bulk crystals, providing great potential for semiconductor devices and applications. Recently, the family of 2D materials has been expanded including but not limited to graphene, hexagonal boron nitride (h-BN), transition metal carbides (TMCs), and transition metal dichalcogenides (TMDCs). Metal-catalyzed chemical vapor deposition (CVD) is an effective method to achieve precise synthesis of these 2D materials. In this review, we focus on designing various binary alloys to realize controllable synthesis of multiple CVD-grown 2D materials and their heterostructures for both fundamental research and practical applications. Further investigations indicated that the design of the catalytic substrate is an important issue, which determines the morphology, domain size, thickness and quality of 2D materials and their heterostructures.

scholarly journals Synthesis and characterization of WS2/graphene/SiC van der Waals heterostructures via WO3−x thin film sulfurization

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jonathan Bradford ◽  
Mahnaz Shafiei ◽  
Jennifer MacLeod ◽  
Nunzio Motta
Keyword(s):  
Vapor Deposition ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Large Area ◽  
Van Der Waals Heterostructures ◽  
Metal Dichalcogenides ◽  
Direct Growth ◽  
Cvd Growth

Abstract Van der Waals heterostructures of monolayer transition metal dichalcogenides (TMDs) and graphene have attracted keen scientific interest due to the complementary properties of the materials, which have wide reaching technological applications. Direct growth of uniform, large area TMDs on graphene substrates by chemical vapor deposition (CVD) is limited by slow lateral growth rates, which result in a tendency for non-uniform multilayer growth. In this work, monolayer and few-layer WS2 was grown on epitaxial graphene on SiC by sulfurization of WO3−x thin films deposited directly onto the substrate. Using this method, WS2 growth was achieved at temperatures as low as 700 °C – significantly less than the temperature required for conventional CVD. Achieving long-range uniformity remains a challenge, but this process could provide a route to synthesize a broad range of TMD/graphene van der Waals heterostructures with novel properties and functionality not accessible by conventional CVD growth.

scholarly journals The Photodetectors Based on Lateral Monolayer MoS2/WS2 Heterojunctions

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Caihong Li ◽  
Juntong Zhu ◽  
Wen Du ◽  
Yixuan Huang ◽  
Hao Xu ◽  
...  
Keyword(s):  
Communication Systems ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Large Area ◽  
Optical Signals ◽  
Metal Dichalcogenides ◽  
One Step ◽  
The One ◽  
Charge Carrier Trapping ◽  
Sharp Interfaces

AbstractMonolayer transition metal dichalcogenides (TMDs) show promising potential for next-generation optoelectronics due to excellent light capturing and photodetection capabilities. Photodetectors, as important components of sensing, imaging and communication systems, are able to perceive and convert optical signals to electrical signals. Herein, the large-area and high-quality lateral monolayer MoS2/WS2 heterojunctions were synthesized via the one-step liquid-phase chemical vapor deposition approach. Systematic characterization measurements have verified good uniformity and sharp interfaces of the channel materials. As a result, the photodetectors enhanced by the photogating effect can deliver competitive performance, including responsivity of ~ 567.6 A/W and detectivity of ~ 7.17 × 1011 Jones. In addition, the 1/f noise obtained from the current power spectrum is not conductive to the development of photodetectors, which is considered as originating from charge carrier trapping/detrapping. Therefore, this work may contribute to efficient optoelectronic devices based on lateral monolayer TMD heterostructures.

In Situ Observation of Nucleation and Growth of Carbon Nanotubes from Iron Carbide Nanoparticles

2008 ◽  
Vol 1142 ◽  
Author(s):  
Hideto Yoshida ◽  
Seiji Takeda ◽  
Tetsuya Uchiyama ◽  
Hideo Kohno ◽  
Yoshikazu Homma
Keyword(s):  
Carbon Nanotubes ◽  
Iron Carbide ◽  
Bulk Diffusion ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Atomic Scale ◽  
In Situ Observation ◽  
Transmission Electron ◽  
Cvd Growth

ABSTRACTNucleation and growth processes of carbon nanotubes (CNTs) in iron catalyzed chemical vapor deposition (CVD) have been observed by means of in-situ environmental transmission electron microscopy. Our atomic scale observations demonstrate that solid state iron carbide (Fe3C) nanoparticles act as catalyst for the CVD growth of CNTs. Iron carbide nanoparticles are structurally fluctuated in CVD condition. Growth of CNTs can be simply explained by bulk diffusion of carbon atoms since nanoparticles are carbide.

Nanoscale Characterization of WSe2for Opto-electronics Applications

MRS Advances ◽  
2017 ◽  
Vol 2 (60) ◽  
pp. 3715-3720 ◽  
Author(s):  
Nirmal Adhikari ◽  
Avra Bandyopadhyay ◽  
Anupama Kaul
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Absorber Layer ◽  
Band Alignment ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Kelvin Probe ◽  
Nanoscale Characterization ◽  
Efficient Charge ◽  
Metal Dichalcogenides

ABSTRACTTwo dimensional (2D) thin transition metal dichalcogenides are being widely investigated for optoelectronics applications. Here, we report on the interfacial study of WSe2with photo-absorber materials for efficient charge transport using Kelvin Probe Force Microscopy (KPFM) for solar cell applications. The WSe2in these experiments was synthesized using Chemical Vapor Deposition (CVD) with a WO3powder and Se pellets as the precursors, where the selenium was placed upstream in an Ar carrier gas within the furnace at a temperature zone of 260-270°C. For the interfacial analysis, nanoscale KPFM measurements show an average surface potential of 125 meV for the CVD synthesized WSe2flakes. KPFM measurements signify that a thin layer of WSe2can be used to suppress back recombination of carriers between the electron transport layer (ETL) and the absorber layer. A proper band alignment between ETL and absorber layer helps to increase the overall device performance, which we will elaborate upon in this work. Capacitance-voltage and capacitance-frequency measurements were measured to study the role of defects.

Controllable growth of multilayered XSe2 (X=W and Mo) for nonlinear optical and optoelectronic applications

2D Materials ◽  
2021 ◽  
Author(s):  
Kun Ye ◽  
Lixuan Liu ◽  
Liying Chen ◽  
Wenlong Li ◽  
Bochong Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Second Harmonic ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Fast Response ◽  
Peak Position ◽  
Metal Dichalcogenides ◽  
Controllable Growth ◽  
Optoelectronic Applications ◽  
Layered Transition Metal

Abstract The layered transition metal dichalcogenides (TMDs) exhibit the intriguing physical properties and potential application in novel electronic devices. However, controllable growth of multilayer TMDs remains challenging. Herein, large-scale and high-quality multilayer prototype TMDs of W(Mo)Se2 were synthesized via chemical vapor deposition. For Raman and PL measurements, 2H and 3R multilayer WSe2 crystals displayed significant layer-dependent peak position and intensity feature. Besides, different from the oscillatory relationship of SHG intensity for odd-even layer numbers in 2H-stacked multilayer WSe2, the second harmonic generation intensity of 3R-stacked ones parabolically increased with the thickness due to the absence of inversion symmetry. For device application, photodetectors based on WSe2 with increasing thickness exhibited p-type (bilayer), ambipolar (trilayer), and n-type (4 layers) semiconductor behaviors, respectively. Furthermore, photodetectors based on the as-synthesized 3R-stacked WSe2 flakes displayed an excellent responsivity (R) of 7.8×103 mA/W, high specific detectivity (Da*) of 1.7×1014 Jones, outstanding external quantum efficiency (EQE) of 8.6×102 %, and fast response time (τRise=57 ms and τFall=53 ms) under 532 nm illumination with bias voltage of Vds=5 V. Similar results have also been achieved in multilayer MoSe2 crystals. All these findings indicate great potential of 3R-stacked TMDs in two-dimensional optoelectronic applications.

scholarly journals Additive manufacturing of patterned 2D semiconductor through recyclable masked growth

2019 ◽  
Vol 116 (9) ◽  
pp. 3437-3442 ◽  
Author(s):  
Yunfan Guo ◽  
Pin-Chun Shen ◽  
Cong Su ◽  
Ang-Yu Lu ◽  
Marek Hempel ◽  
...  
Keyword(s):  
Electronic Materials ◽  
Field Effect Transistors ◽  
2D Materials ◽  
Direct Synthesis ◽  
Scale Up ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Great Promise ◽  
Substrate Engineering ◽  
Metal Dichalcogenides

The 2D van der Waals crystals have shown great promise as potential future electronic materials due to their atomically thin and smooth nature, highly tailorable electronic structure, and mass production compatibility through chemical synthesis. Electronic devices, such as field effect transistors (FETs), from these materials require patterning and fabrication into desired structures. Specifically, the scale up and future development of “2D”-based electronics will inevitably require large numbers of fabrication steps in the patterning of 2D semiconductors, such as transition metal dichalcogenides (TMDs). This is currently carried out via multiple steps of lithography, etching, and transfer. As 2D devices become more complex (e.g., numerous 2D materials, more layers, specific shapes, etc.), the patterning steps can become economically costly and time consuming. Here, we developed a method to directly synthesize a 2D semiconductor, monolayer molybdenum disulfide (MoS2), in arbitrary patterns on insulating SiO2/Si via seed-promoted chemical vapor deposition (CVD) and substrate engineering. This method shows the potential of using the prepatterned substrates as a master template for the repeated growth of monolayer MoS2 patterns. Our technique currently produces arbitrary monolayer MoS2 patterns at a spatial resolution of 2 μm with excellent homogeneity and transistor performance (room temperature electron mobility of 30 cm2 V−1 s−1 and on–off current ratio of 107). Extending this patterning method to other 2D materials can provide a facile method for the repeatable direct synthesis of 2D materials for future electronics and optoelectronics.

scholarly journals Measurement of Quantum Yields of Monolayer TMDs Using Dye-Dispersed PMMA Thin Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1032 ◽  
Author(s):  
Shrawan Roy ◽  
Anir S. Sharbirin ◽  
Yongjun Lee ◽  
Won Bin Kim ◽  
Tae Soo Kim ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Rhodamine 6G ◽  
Composite Films ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Quantum Yields ◽  
Simple Protocol ◽  
Metal Dichalcogenides ◽  
Spatially Homogeneous ◽  
Reference Specimens

In general, the quantum yields (QYs) of monolayer transition metal dichalcogenides (1L-TMDs) are low, typically less than 1% in their pristine state, significantly limiting their photonic applications. Many methods have been reported to increase the QYs of 1L-TMDs; however, the technical difficulties involved in the reliable estimation of these QYs have prevented the general assessment of these methods. Herein, we demonstrate the estimation of the QYs of 1L-TMDs using a poly methyl methacrylate (PMMA) thin film embedded with rhodamine 6G (R6G) as a reference specimen for measuring the QYs of 1L-TMDs. The PMMA/R6G composite films with thicknesses of 80 and 300 nm demonstrated spatially homogeneous emissions with the incorporation of well-dispersed R6G molecules, and may, therefore, be used as ideal reference specimens for the QY measurement of 1L-TMDs. Using our reference specimens, for which the QY ranged from 5.4% to 22.2% depending on the film thickness and R6G concentrations, we measured the QYs of the exfoliated or chemical vapor deposition (CVD)-grown 1L-WS2, -MoSe2, -MoS2, and -WSe2 TMDs. The convenient procedure proposed in this study for preparing the thin reference films and the simple protocol for the QY estimation of 1L-TMDs may enable accurate comparisons of the absolute QYs between the 1L-TMD samples, thereby enabling the development of a method to improve the QY of 1L-TMDs.

scholarly journals Thermal and Photo Sensing Capabilities of Mono- and Few-Layer Thick Transition Metal Dichalcogenides

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 693
Author(s):  
Andrew Voshell ◽  
Mauricio Terrones ◽  
Mukti Rana
Keyword(s):  
Transition Metal ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Cost Effective ◽  
Defect Engineering ◽  
Figures Of Merit ◽  
Sensing Applications ◽  
Metal Dichalcogenides ◽  
Thermal Sensing ◽  
Novel Applications

Two-dimensional (2D) materials have shown promise in various optical and electrical applications. Among these materials, semiconducting transition metal dichalcogenides (TMDs) have been heavily studied recently for their photodetection and thermoelectric properties. The recent progress in fabrication, defect engineering, doping, and heterostructure design has shown vast improvements in response time and sensitivity, which can be applied to both contact-based (thermocouple), and non-contact (photodetector) thermal sensing applications. These improvements have allowed the possibility of cost-effective and tunable thermal sensors for novel applications, such as broadband photodetectors, ultrafast detectors, and high thermoelectric figures of merit. In this review, we summarize the properties arisen in works that focus on the respective qualities of TMD-based photodetectors and thermocouples, with a focus on their optical, electrical, and thermoelectric capabilities for using them in sensing and detection.

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