Evolution of the Polarizing Effect of $\text{MoS}_{2}$
TL;DR: In this article, the authors have explored the polarization behavior of MoS petertodd 2 at three different wavelengths using a polymer-based waveguide and obtained a maximum polarization extinction ratio of 12.6 dB that is achieved at 980 nm.
Abstract: We have explored the polarization behavior of MoS
2
at three different wavelengths using a polymer-based waveguide. The MoS
2
-coated waveguide has been fabricated based on the drop casting method. The maximum polarization extinction ratio of 12.6 dB that is achieved at 980 nm is considered to be the highest, to the best of our knowledge, for the MoS
2
-based waveguide polarizer. It exhibits transverse electric (TE) pass characteristics in the visible wavelength region. The mode field confinement has been computed based on the finite-element method (FEM). Both numerical and experimental results are in very good agreement. These results demonstrate that the few-layer MoS
2
can be considered as a complementary material for graphene-based polarizers.
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TL;DR: The recent advances in this emerging field of integrated GO photonics are reviewed, providing an overview of the optical properties of GO as well as methods for the on-chip integration of GO.
Abstract: With superior optical properties, high flexibility in engineering its material properties, and strong capability for large-scale on-chip integration, graphene oxide (GO) is an attractive solution for on-chip integration of 2D materials to implement functional integrated photonic devices capable of new features. Over the past decade, integrated GO photonics, representing an innovative merging of integrated photonic devices and thin GO films, has experienced significant development, leading to a surge in many applications covering almost every field of optical sciences such as photovoltaics, optical imaging, sensing, nonlinear optics, and light emitting. This paper reviews the recent advances in this emerging field, providing an overview of the optical properties of GO as well as methods for the on-chip integration of GO. The main achievements made in GO hybrid integrated photonic devices for diverse applications are summarized. The open challenges as well as the potential for future improvement are also discussed.
89 citations
TL;DR: In this article, integrated waveguide polarizers and polarization-selective micro-ring resonators (MRRs) were incorporated with layered graphene oxide (GO) films, achieving a high polarization dependent loss (PDL) of ~53.8 dB for the GO-coated waveguide and high polarization extinction ratio of ~8.3dB for the MRR.
Abstract: We experimentally demonstrate integrated waveguide polarizers and polarization-selective micro-ring resonators (MRRs) incorporated with layered graphene oxide (GO) films. We achieve a high polarization dependent loss (PDL) of ~53.8 dB for the GO-coated waveguide and a high polarization extinction ratio of ~8.3 dB for the GO-coated MRR.
89 citations
TL;DR: The PANi/Ag/MoS2/LiCo 0.5Fe2O4 photocatalyst showed an excellent photocatalytic efficiency against bisphenol A (82% removal efficiency) and displayed an exceptional antimicrobial potential towards pathogenic microbes as discussed by the authors.
35 citations
TL;DR: In this article, integrated waveguide polarizers and polarization-selective micro-ring resonators (MRRs) with graphene oxide (GO) films are experimentally demonstrated, and the results show that intrinsic film material loss anisotropy dominates the performance for less than 20 layers whereas polarization dependent mode overlap dominates for thicker layers.
Abstract: Integrated waveguide polarizers and polarization-selective micro-ring resonators (MRRs) incorporated with graphene oxide (GO) films are experimentally demonstrated. CMOS-compatible doped silica waveguides and MRRs with both uniformly coated and patterned GO films are fabricated based on a large-area, transfer-free, layer-by-layer GO coating method that yields precise control of the film thickness. Photolithography and lift-off processes are used to achieve photolithographic patterning of GO films with precise control of the placement and coating length. Detailed measurements are performed to characterize the performance of the devices versus GO film thickness and coating length as a function of polarization, wavelength and power. A high polarization dependent loss of ~53.8 dB is achieved for the waveguide coated with 2-mm-long patterned GO films. It is found that intrinsic film material loss anisotropy dominates the performance for less than 20 layers whereas polarization dependent mode overlap dominates for thicker layers. For the MRRs, the GO coating length is reduced to 50 microns, yielding a ~ 8.3-dB polarization extinction ratio between TE and TM resonances. These results offer interesting physical insights and trends of the layered GO films and demonstrate the effectiveness of introducing GO films into photonic integrated devices to realize high-performance polarization selective components.
35 citations
TL;DR: In this paper , the state-of-the-art fabrication techniques for the on-chip integration of 2D materials are reviewed, which are categorized into material synthesis, onchip transfer, film patterning and property tuning/modification.
Abstract: With compact footprint, low energy consumption, high scalability, and mass producibility, chip‐scale integrated devices are an indispensable part of modern technological change and development. Recent advances in 2D layered materials with their unique structures and distinctive properties have motivated their on‐chip integration, yielding a variety of functional devices with superior performance and new features. To realize integrated devices incorporating 2D materials, it requires a diverse range of device fabrication techniques, which are of fundamental importance to achieve good performance and high reproducibility. This paper reviews the state‐of‐art fabrication techniques for the on‐chip integration of 2D materials. First, an overview of the material properties and on‐chip applications of 2D materials is provided. Second, different approaches used for integrating 2D materials on chips are comprehensively reviewed, which are categorized into material synthesis, on‐chip transfer, film patterning, and property tuning/modification. Third, the methods for integrating 2D van der Waals heterostructures are also discussed and summarized. Finally, the current challenges and future perspectives are highlighted.
28 citations
References
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TL;DR: Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors, and could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.
Abstract: Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5-3 cm(2) V(-1) s(-1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS(2) mobility of at least 200 cm(2) V(-1) s(-1), similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on/off ratios of 1 × 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.
12,477 citations
TL;DR: Ultraensitive monolayer MoS2 phototransistors with improved device mobility and ON current are demonstrated, showing important potential for applications in MoS 2-based integrated optoelectronic circuits, light sensing, biomedical imaging, video recording and spectroscopy.
Abstract: A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.
4,212 citations
TL;DR: A number of methods have been developed to exfoliate layered materials in order to produce monolayer nanosheets, which are ideal for applications that require surface activity.
Abstract: Background Since at least 400 C.E., when the Mayans first used layered clays to make dyes, people have been harnessing the properties of layered materials. This gradually developed into scientific research, leading to the elucidation of the laminar structure of layered materials, detailed understanding of their properties, and eventually experiments to exfoliate or delaminate them into individual, atomically thin nanosheets. This culminated in the discovery of graphene, resulting in a new explosion of interest in two-dimensional materials. Layered materials consist of two-dimensional platelets weakly stacked to form three-dimensional structures. The archetypal example is graphite, which consists of stacked graphene monolayers. However, there are many others: from MoS 2 and layered clays to more exotic examples such as MoO 3 , GaTe, and Bi 2 Se 3 . These materials display a wide range of electronic, optical, mechanical, and electrochemical properties. Over the past decade, a number of methods have been developed to exfoliate layered materials in order to produce monolayer nanosheets. Such exfoliation creates extremely high-aspect-ratio nanosheets with enormous surface area, which are ideal for applications that require surface activity. More importantly, however, the two-dimensional confinement of electrons upon exfoliation leads to unprecedented optical and electrical properties. Liquid exfoliation of layered crystals allows the production of suspensions of two-dimensional nanosheets, which can be formed into a range of structures. (A) MoS 2 powder. (B) WS 2 dispersed in surfactant solution. (C) An exfoliated MoS 2 nanosheet. (D) A hybrid material consisting of WS 2 nanosheets embedded in a network of carbon nanotubes. Advances An important advance has been the discovery that layered crystals can be exfoliated in liquids. There are a number of methods to do this that involve oxidation, ion intercalation/exchange, or surface passivation by solvents. However, all result in liquid dispersions containing large quantities of nanosheets. This brings considerable advantages: Liquid exfoliation allows the formation of thin films and composites, is potentially scaleable, and may facilitate processing by using standard technologies such as reel-to-reel manufacturing. Although much work has focused on liquid exfoliation of graphene, such processes have also been demonstrated for a host of other materials, including MoS 2 and related structures, layered oxides, and clays. The resultant liquid dispersions have been formed into films, hybrids, and composites for a range of applications. Outlook There is little doubt that the main advances are in the future. Multifunctional composites based on metal and polymer matrices will be developed that will result in enhanced mechanical, electrical, and barrier properties. Applications in energy generation and storage will abound, with layered materials appearing as electrodes or active elements in devices such as displays, solar cells, and batteries. Particularly important will be the use of MoS 2 for water splitting and metal oxides as hydrogen evolution catalysts. In addition, two-dimensional materials will find important roles in printed electronics as dielectrics, optoelectronic devices, and transistors. To achieve this, much needs to be done. Production rates need to be increased dramatically, the degree of exfoliation improved, and methods to control nanosheet properties developed. The range of layered materials that can be exfoliated must be expanded, even as methods for chemical modification must be developed. Success in these areas will lead to a family of materials that will dominate nanomaterials science in the 21st century.
3,127 citations
TL;DR: The finding suggests that few-layered MoS₂ nanoplatelets can be useful nonlinear optical material for laser photonics devices, such as passive laser mode locker, Q-switcher, optical limiter, optical switcher and so on.
Abstract: The nonlinear optical property of few-layered MoS2 nanoplatelets synthesized by the hydrothermal exfoliation method was investigated from the visible to the near-infrared band using lasers. Both open-aperture Z-scan and balanced-detector measurement techniques were used to demonstrate the broadband saturable absorption property of few-layered MoS2. To explore its potential applications in ultrafast photonics, we fabricated a passive mode locker for ytterbium-doped fibre laser by depositing few-layered MoS2 onto the end facet of optical fiber by means of an optical trapping approach. Our laser experiment shows that few-layer MoS2-based mode locker allows for the generation of stable mode-locked laser pulse, centered at 1054.3 nm, with a 3-dB spectral bandwidth of 2.7 nm and a pulse duration of 800 ps. Our finding suggests that few-layered MoS2 nanoplatelets can be useful nonlinear optical material for laser photonics devices, such as passive laser mode locker, Q-switcher, optical limiter, optical switcher and so on.
991 citations
TL;DR: In this paper, the coupling, guiding and polarizing of electromagnetic waves in graphene and demonstrate a graphene-based fibre polarizer that exhibits a transverse electric-pass polarization at an extinction ratio of up to ∼27 dB in the telecommunications band.
Abstract: Scientists study the coupling, guiding and polarizing of electromagnetic waves in graphene and demonstrate a graphene-based fibre polarizer that exhibits a transverse-electric-pass polarization at an extinction ratio of up to ∼27 dB in the telecommunications band.
969 citations