scholarly journals Electrical suppression of all nonradiative recombination pathways in monolayer semiconductors

Science ◽  
2019 ◽  
Vol 364 (6439) ◽  
pp. 468-471 ◽  
Author(s):  
Der-Hsien Lien ◽  
Shiekh Zia Uddin ◽  
Matthew Yeh ◽  
Matin Amani ◽  
Hyungjin Kim ◽  
...  
Keyword(s):  
Defect Density ◽  
Transition Metal Dichalcogenides ◽  
Optoelectronic Device ◽  
Nonradiative Recombination ◽  
Native Defect ◽  
Stringent Requirement ◽  
Electrostatic Doping ◽  
Metal Dichalcogenides ◽  
Device Applications ◽  
Chemical Passivation

Defects in conventional semiconductors substantially lower the photoluminescence (PL) quantum yield (QY), a key metric of optoelectronic performance that directly dictates the maximum device efficiency. Two-dimensional transition-metal dichalcogenides (TMDCs), such as monolayer MoS2, often exhibit low PL QY for as-processed samples, which has typically been attributed to a large native defect density. We show that the PL QY of as-processed MoS2 and WS2 monolayers reaches near-unity when they are made intrinsic through electrostatic doping, without any chemical passivation. Surprisingly, neutral exciton recombination is entirely radiative even in the presence of a high native defect density. This finding enables TMDC monolayers for optoelectronic device applications as the stringent requirement of low defect density is eased.

scholarly journals Electrical and optical properties of transition metal dichalcogenides on talc dielectrics

Nanoscale ◽  
2021 ◽  
Author(s):  
Darren Nutting ◽  
Gabriela Augusta Prando ◽  
Marion Severijnen ◽  
Ingrid Barcelos ◽  
Shi Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Defect Density ◽  
Transition Metal Dichalcogenides ◽  
Dielectric Materials ◽  
High Quality ◽  
Electrical And Optical Properties ◽  
Metal Dichalcogenides ◽  
Vdw Heterostructure ◽  
Heterostructure Devices

Advanced van der Waals (vdW) heterostructure devices rely on the incorporation of high quality dielectric materials which need to possess a low defect density as well as being atomically smooth...

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.

Remarkably high thermal-driven MoS2 grain boundary migration mobility and its implications on defect healing

Nanoscale ◽  
2020 ◽  
Vol 12 (34) ◽  
pp. 17746-17753
Author(s):  
Xiangjun Liu ◽  
Zhi Gen Yu ◽  
Gang Zhang ◽  
Yong-Wei Zhang
Keyword(s):  
Robust Control ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Boundary Migration ◽  
Transition Metal Dichalcogenides ◽  
Grain Boundary Migration ◽  
Two Dimensional ◽  
Defect Healing ◽  
Metal Dichalcogenides ◽  
Device Applications

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) hold great potential for many important device applications, such as field effect transistors and sensors, which require a robust control of defect type, density, and distribution.

scholarly journals 2D-MoS2 goes 3D: transferring optoelectronic properties of 2D MoS2 to a large-area thin film

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Melanie Timpel ◽  
Giovanni Ligorio ◽  
Amir Ghiami ◽  
Luca Gavioli ◽  
Emanuele Cavaliere ◽  
...  
Keyword(s):  
Thin Film ◽  
Electronic Devices ◽  
Transition Metal Dichalcogenides ◽  
Optical Emission ◽  
Optoelectronic Device ◽  
Large Area ◽  
2D Semiconductors ◽  
Optical And Electronic Properties ◽  
Growth Method ◽  
Metal Dichalcogenides

AbstractThe ongoing miniaturization of electronic devices has boosted the development of new post-silicon two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, one of the most prominent materials being molybdenum disulfide (MoS2). A major obstacle for the industrial production of MoS2-based devices lies in the growth techniques. These must ensure the reliable fabrication of MoS2 with tailored 2D properties to allow for the typical direct bandgap of 1.9 eV, while maintaining large-area growth and device compatibility. In this work, we used a versatile and industrially scalable MoS2 growth method based on ionized jet deposition and annealing at 250 °C, through which a 3D stable and scalable material exhibiting excellent electronic and optical properties of 2D MoS2 is synthesized. The thickness-related limit, i.e., the desired optical and electronic properties being limited to 2D single/few-layered MoS2, was overcome in the thin film through the formation of encapsulated highly crystalline 2D MoS2 nanosheets exhibiting a bandgap of 1.9 eV and sharp optical emission. The newly synthesized 2D-in-3D MoS2 structure will facilitate device compatibility of 2D materials and confer superior optoelectronic device function.

scholarly journals Air-stable, efficient electron doping of monolayer MoS2 by salt–crown ether treatment

Nanoscale ◽  
2021 ◽  
Author(s):  
Hiroto Ogura ◽  
Masahiko Kaneda ◽  
Yusuke Nakanishi ◽  
Yoshiyuki Nonoguchi ◽  
Jiang Pu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Crown Ether ◽  
Transition Metal Dichalcogenides ◽  
Monolayer Mos2 ◽  
Electron Doping ◽  
Highly Efficient ◽  
Metal Dichalcogenides ◽  
Device Applications ◽  
Carrier Doping ◽  
Ether Treatment

To maximize the potential of transition-metal dichalcogenides (TMDCs) in device applications, the development of a sophisticated technique for stable and highly efficient carrier doping is critical. Here, we report the...

scholarly journals Broadband Optical Properties of Atomically Thin PtS2 and PtSe2

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3269
Author(s):  
Georgy A. Ermolaev ◽  
Kirill V. Voronin ◽  
Mikhail K. Tatmyshevskiy ◽  
Arslan B. Mazitov ◽  
Aleksandr S. Slavich ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Constants ◽  
Transition Metal Dichalcogenides ◽  
Optoelectronic Device ◽  
High Refractive Index ◽  
Broadband Absorption ◽  
Wide Range ◽  
Out Of Plane ◽  
Metal Dichalcogenides ◽  
Infrared Wavelengths

Noble transition metal dichalcogenides (TMDCs) such as PtS2 and PtSe2 show significant potential in a wide range of optoelectronic and photonic applications. Noble TMDCs, unlike standard TMDCs such as MoS2 and WS2, operate in the ultrawide spectral range from ultraviolet to mid-infrared wavelengths; however, their properties remain largely unexplored. Here, we measured the broadband (245–3300 nm) optical constants of ultrathin PtS2 and PtSe2 films to eliminate this gap and provide a foundation for optoelectronic device simulation. We discovered their broadband absorption and high refractive index both theoretically and experimentally. Based on first-principle calculations, we also predicted their giant out-of-plane optical anisotropy for monocrystals. As a practical illustration of the obtained optical properties, we demonstrated surface plasmon resonance biosensors with PtS2 or PtSe2 functional layers, which dramatically improves sensor sensitivity by 60 and 30%, respectively.

scholarly journals Methane-Mediated Vapor Transport Growth of Monolayer WSe2 Crystals

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1642
Author(s):  
Hyeon-Sik Jang ◽  
Jae-Young Lim ◽  
Seog-Gyun Kang ◽  
Sang-Hwa Hyun ◽  
Sana Sandhu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal Dichalcogenides ◽  
Nucleation Density ◽  
Large Area ◽  
High Quality ◽  
Catalytic Growth ◽  
Production Methods ◽  
Metal Dichalcogenides ◽  
Device Applications ◽  
P Type

The electrical and optical properties of semiconducting transition metal dichalcogenides (TMDs) can be tuned by controlling their composition and the number of layers they have. Among various TMDs, the monolayer WSe2 has a direct bandgap of 1.65 eV and exhibits p-type or bipolar behavior, depending on the type of contact metal. Despite these promising properties, a lack of efficient large-area production methods for high-quality, uniform WSe2 hinders its practical device applications. Various methods have been investigated for the synthesis of large-area monolayer WSe2, but the difficulty of precisely controlling solid-state TMD precursors (WO3, MoO3, Se, and S powders) is a major obstacle to the synthesis of uniform TMD layers. In this work, we outline our success in growing large-area, high-quality, monolayered WSe2 by utilizing methane (CH4) gas with precisely controlled pressure as a promoter. When compared to the catalytic growth of monolayered WSe2 without a gas-phase promoter, the catalytic growth of the monolayered WSe2 with a CH4 promoter reduced the nucleation density to 1/1000 and increased the grain size of monolayer WSe2 up to 100 μm. The significant improvement in the optical properties of the resulting WSe2 indicates that CH4 is a suitable candidate as a promoter for the synthesis of TMD materials, because it allows accurate gas control.

Effect of Addition of KI on the Hydrothermal Growth of ZnO Nanostructures Towards Hybrid Optoelectronic Device Applications

2016 ◽  
Vol 16 (4) ◽  
pp. 3301-3306 ◽  
Author(s):  
Anubha Bilgaiyan ◽  
Tejendra Dixit ◽  
Gaurav Kapil ◽  
Shyam S Pandey ◽  
Shuji Hayase ◽  
...  
Keyword(s):  
Defect Density ◽  
Zno Nanorods ◽  
Optoelectronic Device ◽  
Hydrothermal Growth ◽  
Visible Range ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
Zno Nanosheets ◽  
Device Applications ◽  
Structural And Optoelectronic Properties

We report the structural and optoelectronic properties of Zinc oxide (ZnO) nanostructures prepared by hydrothermal method. The morphological, structural and optical properties of the grown ZnO nanostructures were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectroscopy (PL) respectively. Upon addition of relatively small amount of KI during the in-situ hydrothermal growth the nanorods were formed, further increasing the concentration led to increased diameter of these nanorods and finally at relatively higher concentration of KI, ZnO nanosheets were formed. Later these structures were used to fabricate bi-layer ZnO/P3HT based hybrid photodiode. Subsequent hybrid photodiode measurement with ZnO nanorods and ZnO nanosheets indicated that the nanosheets exhibited improved photodiode response. Compared to the ZnO nanorod/P3HT devices, the optimized photodiode with the dense ZnO nanosheets/P3HT have shown significant increase in the rectification ratio and the photosenstivity from 3.21 to 1420 and from 5.85 to 1330 respectively. The enhanced photodiode response of bi-layered devices consisting of ZnO nanosheets indicated that optimizing the shape and size of ZnO nanostructures had a significant influence on the overall photocurrent and the observed results have been explained on the basis of reduction in the defect density with pronounced absorption in the UV region, thus leading to improved transmission of light in the visible range through these layers.

scholarly journals Evolution of defect formation during atomically precise desulfurization of monolayer MoS2

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jong-Young Lee ◽  
Jong Hun Kim ◽  
Yeonjoon Jung ◽  
June Chul Shin ◽  
Yangjin Lee ◽  
...  
Keyword(s):  
Transition Metal ◽  
Symmetry Breaking ◽  
Defect Formation ◽  
Defect Density ◽  
Contact Stiffness ◽  
Hydrogen Plasma ◽  
Transition Metal Dichalcogenides ◽  
Chemical Properties ◽  
Atomic Scale ◽  
Metal Dichalcogenides

AbstractStructural symmetry-breaking is a key strategy to modify the physical and chemical properties of two-dimensional transition metal dichalcogenides. However, little is known about defect formation during this process. Here, with atomic-scale microscopy, we investigate the evolution of defect formation in monolayer MoS2 exposed indirectly to hydrogen plasma. At the beginning of the treatment only top-layer sulfur atoms are removed, while vacancies and the molybdenum atomic layer are maintained. As processing continues, hexagonal-shaped nanocracks are generated along the zigzag edge during relaxation of defect-induced strain. As defect density increases, both photoluminescence and conductivity of MoS2 gradually decreases. Furthermore, MoS2 showed increased friction by 50% due to defect-induced contact stiffness. Our study reveals the details of defect formation during the desulfurization of MoS2 and helps to design the symmetry-breaking transition metal dichalcogenides, which is of relevance for applications including photocatalyst for water splitting, and Janus heterostructures.

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