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.

scholarly journals High-Performance Photodetectors Based on Lateral Monolayer MoS2/WS2 Heterojunctions

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

Abstract Monolayer 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 (CVD) 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 x 1011 Jones. In addition, the 1/f noise obtained from the current power spectrum is adverse 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.

Large-area synthesis of transition metal dichalcogenides via CVD and solution-based approaches and their device applications

Nanoscale ◽  
2021 ◽  
Author(s):  
Anh Tuan Hoang ◽  
Kairui Qu ◽  
Xiang Chen ◽  
Jong-Hyun Ahn
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Transition Metal ◽  
Vapor Deposition ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Large Area ◽  
Wafer Scale ◽  
Metal Dichalcogenides ◽  
Device Applications

This article reviews the latest advances in the synthesis of wafer-scale thin films using chemical vapor deposition and solution-based methods and various device applications.

Large scale 2D/3D hybrids based on gallium nitride and transition metal dichalcogenides

Nanoscale ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 336-341 ◽  
Author(s):  
Kehao Zhang ◽  
Bhakti Jariwala ◽  
Jun Li ◽  
Natalie C. Briggs ◽  
Baoming Wang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Vapor Deposition ◽  
Large Scale ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Large Area ◽  
Metal Dichalcogenides ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Large area 2D MoS2 and WSe2 are integrated on 3D GaN by metal organic chemical vapor deposition (MOCVD). The thickness-dependent vertical tunneling and interlayer charge transfer is carefully studied. This work shows that few layer WSe2 film is the appropriate choice towards device application of synthetic 2D/3D heterostructures.

scholarly journals Optical Constants and Structural Properties of Epitaxial MoS2 Monolayers

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1411
Author(s):  
Georgy A. Ermolaev ◽  
Marwa A. El-Sayed ◽  
Dmitry I. Yakubovsky ◽  
Kirill V. Voronin ◽  
Roman I. Romanov ◽  
...  
Keyword(s):  
Structural Properties ◽  
Transition Metal Dichalcogenides ◽  
Single Layer ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Structural Quality ◽  
Large Area ◽  
Exciting Potential ◽  
Metal Dichalcogenides ◽  
Mos2 Monolayers

Two-dimensional layers of transition-metal dichalcogenides (TMDs) have been widely studied owing to their exciting potential for applications in advanced electronic and optoelectronic devices. Typically, monolayers of TMDs are produced either by mechanical exfoliation or chemical vapor deposition (CVD). While the former produces high-quality flakes with a size limited to a few micrometers, the latter gives large-area layers but with a nonuniform surface resulting from multiple defects and randomly oriented domains. The use of epitaxy growth can produce continuous, crystalline and uniform films with fewer defects. Here, we present a comprehensive study of the optical and structural properties of a single layer of MoS2 synthesized by molecular beam epitaxy (MBE) on a sapphire substrate. For optical characterization, we performed spectroscopic ellipsometry over a broad spectral range (from 250 to 1700 nm) under variable incident angles. The structural quality was assessed by optical microscopy, atomic force microscopy, scanning electron microscopy, and Raman spectroscopy through which we were able to confirm that our sample contains a single-atomic layer of MoS2 with a low number of defects. Raman and photoluminescence spectroscopies revealed that MBE-synthesized MoS2 layers exhibit a two-times higher quantum yield of photoluminescence along with lower photobleaching compared to CVD-grown MoS2, thus making it an attractive candidate for photonic applications.

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.

Large area chemical vapor deposition of monolayer transition metal dichalcogenides and their temperature dependent Raman spectroscopy studies

Nanoscale ◽  
2016 ◽  
Vol 8 (5) ◽  
pp. 3008-3018 ◽  
Author(s):  
Amit S. Pawbake ◽  
Mahendra S. Pawar ◽  
Sandesh R. Jadkar ◽  
Dattatray J. Late
Keyword(s):  
Raman Spectroscopy ◽  
Vapor Deposition ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapor ◽  
Lateral Size ◽  
Large Area ◽  
Temperature Dependent ◽  
Chemical Vapor Deposited ◽  
Metal Dichalcogenides ◽  
Spectroscopy Studies

We investigate the growth mechanism and temperature dependent Raman spectroscopy of chemical vapor deposited large area monolayer of MoS2, MoSe2, WS2 and WSe2 nanosheets up to 70 μm in lateral size.

scholarly journals Realization of Lasing Emission from One Step Fabricated WSe2 Quantum Dots

Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 538
Author(s):  
Pengpeng Ren ◽  
Wenfei Zhang ◽  
Yiqun Ni ◽  
Di Xiao ◽  
Honghao Wan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Transition Metal Dichalcogenides ◽  
Laser Cavity ◽  
Threshold Value ◽  
Gain Medium ◽  
Excitation Wavelength ◽  
Excitation Threshold ◽  
Ultrasonic Probe ◽  
Metal Dichalcogenides ◽  
One Step

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) quantum dots (QDs) are the vanguard due to their unique properties. In this work, WSe2 QDs were fabricated via one step ultrasonic probe sonication. Excitation wavelength dependent photoluminescence (PL) is observed from WSe2 QDs. Room-temperature lasing emission which benefits from 3.7 times enhancement of PL intensity by thermal treatment at ~470 nm was achieved with an excitation threshold value of ~3.5 kW/cm2 in a Fabry–Perot laser cavity. To the best of our knowledge, this is the first demonstration of lasing emission from TMDCs QDs. This indicates that TMDCs QDs are a superior candidate as a new type of laser gain medium.

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.

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