scholarly journals MoS2 Surface Structure Tailoring via Carbonaceous Promoter

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Yumeng Shi ◽  
Henan Li ◽  
Jen It Wong ◽  
Xiaoting Zhang ◽  
Ye Wang ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Transition Metal Dichalcogenides ◽  
Lithium Ion ◽  
Chemical Vapor ◽  
Easy Access ◽  
Chemical Vapor Deposition Method ◽  
Controlled Synthesis ◽  
Growth Promoter ◽  
Flower Shape ◽  
Metal Dichalcogenides

Abstract Atomically thin semiconducting transition-metal dichalcogenides have been attracting lots of attentions, particularly, molybdenum disulfide (MoS2) monolayers show promising applications in field effect transistors, optoelectronics and valleytronics. However, the controlled synthesis of highly crystalline MoS2 remain a challenge especially the systematic approach to manipulate its structure and morphology. Herein, we report a method for controlled synthesis of highly crystalline MoS2 by using chemical vapor deposition method with carbonaceous materials as growth promoter. A uniform and highly crystalline MoS2 monolayer with the grain size close to 40 μm was achieved. Furthermore, we extend the method to the manipulation of MoS2 morphology, flower-shape vertical grown MoS2 layers were obtained on growth promoting substrates. This simple approach allows an easy access of highly crystalline MoS2 layers with morphology tuned in a controllable manner. Moreover, the flower-shape MoS2 grown on graphene oxide film used as an anode material for lithium-ion batteries showed excellent electrochemical performance.

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.

Electrical Characteristics of a Chemical Vapor Deposition-Grown MoS2 Monolayer-Based Field Effect Transistor

2020 ◽  
Vol 15 (6) ◽  
pp. 673-678
Author(s):  
Soo-Young Kang ◽  
Gil-Sung Kim ◽  
Min-Sung Kang ◽  
Won-Yong Lee ◽  
No-Won Park ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Electrical Characteristics ◽  
Mos2 Monolayer ◽  
2D Semiconductors ◽  
Metal Dichalcogenides

Transition metal dichalcogenides (TMDs) are layered two-dimensional (2D) semiconductors and have received significant attention for their potential application in field effect transistors (FETs), owing to their inherent characteristics. Among the various reported 2D TMD materials, monolayer (ML) molybdenum disulfide (MoS2) is being considered as a promising channel material for the fabrication of future transistors with gate lengths as small as ∼1 nm. In this work, we present chemical vapor deposition-grown triangular ML MoS2 with a lateral size of ∼22 μm and surface coverage of ∼47%, as well as a PMMA-based wet transfer process for depositing the as-grown triangular ML MoS2 flakes onto a SiO2 (∼100 nm)/p++-Si substrate. Additionally, we demonstrate the fabrication of an n-type MoS2-based FET device and study its electrical characteristics as a function of the gate voltage. Our FET device shows an excellent on/off ratio of ∼106, an off-state leakage current of less than 10– 12 A, and a field effect mobility of ∼10.4 cm2/Vs at 300 K.

scholarly journals Enhanced Electrical Performance of Monolayer MoS2 with Rare Earth Element Sm Doping

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 769
Author(s):  
Shijie Li ◽  
Shidai Tian ◽  
Yuan Yao ◽  
Meng He ◽  
Li Chen ◽  
...  
Keyword(s):  
Rare Earth ◽  
Energy Levels ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Electrical Performance ◽  
Chemical Vapor Deposition Method ◽  
Monolayer Mos2 ◽  
Pressure Chemical ◽  
Metal Dichalcogenides ◽  
Type Character

Rare earth (RE) element-doped two-dimensional (2D) transition metal dichalcogenides (TMDCs) with applications in luminescence and magnetics have received considerable attention in recent years. To date, the effect of RE element doping on the electronic properties of monolayer 2D-TMDCs remains unanswered due to challenges including the difficulty of achieving valid monolayer doping and introducing RE elements with distinct valence and atomic configurations. Herein, we report a unique strategy to grow the Sm-doped monolayer MoS2 film by using an atmospheric pressure chemical vapor deposition method with the substrate face down on top of the growth source. A stable monolayer triangular Sm-doped MoS2 was achieved. The threshold voltage of an Sm-doped MoS2-based field effect transistor (FET) moved from −12 to 0 V due to the p-type character impurity state introduced by Sm ions in monolayer MoS2. Additionally, the electrical performance of the monolayer MoS2-based FET was improved by RE element Sm doping, including a 500% increase of the on/off current ratio and a 40% increase of the FET’s mobility. The electronic property enhancement resulted from Sm doping MoS2, which led internal lattice strain and changes in Fermi energy levels. These findings provide a general approach to synthesize RE element-doped monolayer 2D-TMDCs and to enrich their applications in electrical devices.

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.

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.

Anti-Ambipolar Field-Effect Transistors Based On Few-Layer 2D Transition Metal Dichalcogenides

2016 ◽  
Vol 8 (24) ◽  
pp. 15574-15581 ◽  
Author(s):  
Yongtao Li ◽  
Yan Wang ◽  
Le Huang ◽  
Xiaoting Wang ◽  
Xingyun Li ◽  
...  
Keyword(s):  
Transition Metal ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Transition Metal Dichalcogenides ◽  
Metal Dichalcogenides

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.

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