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Planar hot-electron photodetector utilizing high refractive index MoS<sub>2</sub> in fabry-p??rot perfect absorber
摘要： Hot electron photodetection (HEPD) excited by surface plasmon can circumvent bandgap limitations, opening pathways for additional energy harvesting. However, the costly and time-consuming lithography and electron beam lithography-free hot electron photodetector based on the Fabry-Pérot resonance has long been a barrier for large-area and mass production of HEPD. In this paper, we proposed a planar and electron beam lithography-free hot electron photodetector based on the Fabry-Pérot resonance composed of Au/MoS2/Au cavity. The hot electron photodetector has a nanoscale thickness, high spectral tenability, and multicolour photoresponse in the near-infrared region due to the increased round-trip phase shift by using high refractive index MoS2. We predict that the photoresponsivity can achieve up to 23.6 mA/W when double cavities are integrated with the Fabry-Pérot cavity. The proposed hot electron photodetector that has a nanoscale thickness and planar stacking is a perfect candidate for large-area and mass production of HEPD.
关键词： Hot electron,photodetection,Molybdenum disulphide,Fabry-Pérot resonance,perfect absorption
更新于2025-09-23 15:21:01
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Atomistic mechanisms of seeding promoter-controlled growth of molybdenum disulphide
摘要： Seeding promoters facilitate the nucleation and growth of transition metal dichalcogenides in chemical vapor deposition (CVD). However, sophisticated roles of seeding promoter remain unclear. Here, adopting triangular-shaped crystal violet (CV) consisting of nonpolar and polar parts as the seeding promoter, we study the role of seeding promoter for the growth of molybdenum disulfide (MoS2). We systematically control the geometrical configuration of CV on SiO2/Si substrate by changing the solvent polarity and find that it strongly affects the growth of monolayer or multilayer MoS2 domains via CVD. Monolayer MoS2 domains were predominantly grown on randomly lying-down CV configurations on SiO2/Si substrate, whereas multilayer MoS2 domains are synthesized at concentrated polar parts in CV micelle on the substrate. Density functional theory calculations reveal that the initial nucleation step for the MoS2 growth is the adsorption of S on CV and the most favourable S adsorption site is the polar part in CV. Furthermore, it is found that the polar CV part mediates the CV adsorption to SiO2 and additionally strengthened in the lying-down CV configuration. Enhancing the thermal stability as well as hindering the re-aggregation of CV at high temperature, the lying down CV configuration allows the predominant growth of monolayer MoS2.
关键词： seeding promoter,molybdenum disulphide,chemical vapour deposition,transition metal dichalcogenides
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Spectroscopic and Structural Properties of Yb <sup>3+</sup> -Doped and Undoped 2D-Mos <sub/>2</sub> Thin Films for Optoelectronic and Photonic Device Applications
摘要： Molybdenum disulphide (MoS2) has layered structure and is classed as a transition metal-disulphide (TMD) material. Recently it has drawn significant attention for exploring optoelectronic and photonic properties on sub-nanometre scale, with a potential for accessing quantum interactions [1]. The electronic structure and stoichiometry of TMDs make them distinguishable from the metallic graphene, as the TMDs depict a clear bandgap, as in compound semiconductors [2], which is quite attractive for device engineering and applications in photovoltaic, energy storage, and bandgap engineered light-sources [3]. In this research, the fabrication of undoped and Yb3+-ion doped MoS2 nanometre (nm)-scale thin films are discussed using femto-second pulsed laser deposition (fs-PLD) and the structural and spectroscopic properties of fs-PLD are compared with liquid-phase epitaxy grown undoped MoS2 films. Such a comparative analysis may offer materials fabrication platform in future for engineering optoelectronic and photonic devices on silica glass and silicon platforms.
关键词： DFT,Raman spectroscopy,nonlinear optical properties,Molybdenum disulphide,fs-PLD,photonic devices,Yb3+-doped,optoelectronic,thin films
更新于2025-09-19 17:13:59
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Ultrasensitive broadband photodetector using electrostatically conjugated MoS2-upconversion nanoparticle nanocomposite
摘要： Hybrid or composite nanomaterials have emerged that demonstrates superior optoelectronic performance over pure nanomaterials that lacks broadband usage, or responsivity, or both, mainly because of the limitation of the collection of photogenerated carriers. We have addressed this problem by using a composite of MoS2 and a multi-photon absorbing lanthanide doped upconversion nanoparticles (UCNPs), that emits in the visible, to make a photodetector (PD) device with ultrahigh broadband responsivity. Single flake MoS2 electrostatically conjugated with UCNPs were used to fabricate the PD device with platinum, and gold contacts. The device was irradiated with UV-to-NIR illumination, at different power density, to study its broadband photosensitivity. Photoresponsivities in excess of 100 AW-1 is easily obtained; a highest responsivity of 1254 AW-1 is reported for 980 nm at 1.0 V bias. An unprecedented normalized gain of 7.12 x 10-4 cm2 V-1, and Detectivity of 1.05 x 1015 Jones (@980 nm, 1V) was obtained which is, to the best of our knowledge, the highest reported till date for this device class. Under vacuum conditions even higher values of these device parameters were obtained, while losing on the response speeds. The photoresponsivity in the nanocomposite followed the trend of the convoluted optical absorption of the individual components. Real application of the PD device was demonstrated using non-laser domestic appliances such as sodium vapour lamp, mobile phone flash light, and air-condition remote controller.
关键词： Nanocomposites,Responsivity,Molybdenum disulphide,Photodetectors,Broadband,Upconversion nanoparticles
更新于2025-09-16 10:30:52
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Improved resistive switching performance in Cu-cation migrated MoS2 based ReRAM device incorporated with tungsten nitride bottom electrode
摘要： The resistive switching characteristics of sputtered deposited molybdenum disulphide (MoS2) thin film has been investigated in Cu/MoS2/W2N stack configuration for Resistive Random Access Memory (ReRAM) application. The benefits of incorporating tungsten nitride (W2N) as a bottom electrode material were demonstrate by stability in operating voltages, good endurance (103 cycles) and long non-volatile retention (103 s) characteristics. Resistive switching properties in Cu/MoS2/W2N structure are induced by the formation/disruption of Cu conducting filaments in MoS2 thin film. Ohmic law and space charge limited current (SCLC) are observed as dominant conduction mechanism in low resistance state (LRS) and high resistance state (HRS) respectively. This study suggests the application of MoS2 thin films with W2N bottom electrode for next generation non-volatile ReRAM application.
关键词： Conducting filament,Resistive switching,Molybdenum disulphide,Thin films,Tungsten nitride
更新于2025-09-10 09:29:36
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Facile construction of a molybdenum disulphide/zinc oxide nanosheet hybrid for an advanced photocatalyst
摘要： Zinc oxide, an important semiconductor material with good stability, is widely used in photocatalytic degradation of organic pollutants. MoS2 is a two-dimensional semiconductor material. When molybdenum disulphide has more sulfur elements exposed, the photocatalytic activity can be improved. Through the hydrothermal method, zinc oxide nanosheets and molybdenum disulphide nanosheets were successfully supported to form MoS2-ZnO heterojunctions. The surface area of these heterojunctions is large, and they expose more sulfur elements which can effectively promote the separation of photo-generated electrons and holes, and improve the photocatalytic performance of MoS2-ZnO heterojunctions. The photocatalytic degradation of Rhodamine B by MoS2-ZnO heterojunctions was completed in one hour. MoS2-ZnO heterojunctions are environmentally friendly photocatalysts that do not pollute the environment when they degrade organic pollutants in water.
关键词： Photocatalyst,Zinc oxide,Molybdenum disulphide,Heterojunction
更新于2025-09-09 09:28:46