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1.
    
It is crucial to develop advanced optoelectronic devices that incorporate multiple functions, including sensing, storage, and computing, which is considered at the forefront of semiconductor optoelectronics to meet emerging functional diversification. In this study, by stacking the n-type Ga2O3 with the n-type MoS2 flakes, a Ga2O3/MoS2 heterostructure optoelectronic device with high rectification ratio of ≈105 and on/off ratio of ≈108 is fabricated, which achieves high detectivity of 1.34 × 109 Jones and high responsivity of 28.92 mA/W. More importantly, the Ga2O3/MoS2 heterostructure device shows potential ability to integrate sensing and memorizing, simultaneously, which can be used as artificial neuromorphic synaptic. The device exhibits excellent photo-induced synaptic functions including short-term plasticity, long-term plasticity, and paired-pulse facilitation, realizing the ability to couple light and electrical signals by Pavlovian associative learning. At last, the device also demonstrates the information processing ability to act as optoelectronic logic gate AND by synergistically regulating the light on/off states and gate voltage. The research introduces an innovative strategy for the development of next-generation optoelectronic devices which are highly integrated with sensing, memory, and logic processing functions, demonstrating great application prospects in constructing an efficient artificial neuromorphic visual and logic systems.  相似文献   

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3.
    
Flexible 2D inorganic MoS2 and organic g‐C3N4 hybrid thin film photodetectors with tunable composition and photodetection properties are developed using simple solution processing. The hybrid films fabricated on paper substrate show broadband photodetection suitable for both UV and visible light with good responsivity, detectivity, and reliable and rapid photoswitching characteristics comparable to monolayer devices. This excellent performance is retained even after the films are severely deformed at a bending radius of ≈2 mm for hundreds of cycles. The detailed charge transfer and separation processes at the interface between the 2D materials in the hybrid films are confirmed by femtosecond transient absorption spectroscopy with broadband capability.  相似文献   

4.
    
Molecular doping is a powerful, tuneable, and versatile method to modify the electronic properties of 2D transition metal dichalcogenides (TMDCs). While electron transfer is an isotropic process, dipole‐induced doping is a collective phenomenon in which the orientation of the molecular dipoles interfaced to the 2D material is key to modulate and boost this electronic effect, despite it is not yet demonstrated. A novel method toward the molecular functionalization of monolayer MoS2 relying on the molecular self‐assembly of metal phthalocyanine and the orientation‐controlled coordination chemistry of axial ligands is reported here. It is demonstrated that the subtle variation of position and type of functional groups exposed on the pyridinic ligand, yields a molecular dipole with programed magnitude and orientation which is capable to strongly influence the opto‐electronic properties of monolayer MoS2. In particular, experimental results revealed that both p‐ and n‐type doping can be achieved by modulating the charge carrier density up to 4.8 1012 cm?2. Density functional theory calculations showed that the doping mechanism is primarily resulting from the effect of dipole‐induced doping rather than charge transfer. The strategy to dope TMDCs is a highly modulable and robust, and it enables to enrich the functionality of 2D materials‐based devices for high‐performance applications in optoelectronics.  相似文献   

5.
    
1/f noise represents the dominant source of noise in the low-frequency range in several physical systems, including field-effect transistors. Its investigation can provide very important information on the fabrication process, highlighting the steps that are more prone to the introduction of defects. Here, 1/f noise in bilayer MoS2 transistors on paper with inkjet-printed Ag contacts and hBN dielectric is investigated. These devices are promising building blocks for future low-cost, flexible, and easily recyclable disposable electronics. The analysis of 1/f noise, performed following Hooge's empirical approach, results in a Hooge parameter ≈1–10, which is comparable to those reported for bilayer MoS2 transistors on SiO2. The present results indicate that the noise properties of the investigated devices are stable against substrate bending and are mainly determined by the printing of the dielectric, while not being sensibly affected by the use of the paper substrate. These results are promising for the further development of low noise 2D material-based flexible electronics on paper.  相似文献   

6.
    
2D transition metal dichalcogenides (TMDs) are promising semiconductive films for applications in future devices due to their prosperous and tunable band structures. However, most TMD-based top gate transistors suffer from a significant doping effect in the channel due to the subsequent deposition high-k dielectric layer and metal gate, which limits their practical applications. In this work, the channel doping effect caused by various processing steps based on mechanical exfoliated MoS2 sheets is systematically investigated. This work illustrates a clear correlation among these steps and provides a simple and efficient methodology to realize high-performance enhancement mode MoS2 field effect transistors, which can be extended to other 2D materials.  相似文献   

7.
    
Two‐dimensional inorganic materials are emerging as a premiere class of materials for fabricating modern electronic devices. The interest in 2D layered transition metal dichalcogenides is especially high. Particularly, 2D MoS2 is being heavily researched due to its novel functionalities and its suitability for a wide range of electronic and optoelectronic applications. In this article, the progress in mono/few layer(s) MoS2 research is reviewed by focusing primarily on the layer dependent evolution of crystal, phonon, and electronic structure. The review includes extensive detail into the methodologies adapted for single or few layer(s) MoS2 growth. Further, the review covers the versatility of 2D MoS2 for a broad range of device applications. Recent advancements in the field of van der Waals heterostructures are also highlighted at the end of the review.  相似文献   

8.
    
Heterostructures composed of multiple layers of different atomically thin materials are of interest due to their unique properties and potential for new device functionality. MoS2‐graphene heterostructures have shown promise as photodetectors and vertical tunnel transistors. However, progress is limited by the typically micrometer‐scale devices and by the multiple alignments required for fabrication when utilizing mechanically exfoliated material. Here, the synthesis of large‐area, continuous, and uniform MoS2 monolayers directly on graphene by chemical vapor deposition is reported, resulting in heterostructure samples on the centimeter scale with the possibility for even larger lateral dimensions. Atomic force microscopy, photoluminescence, X‐ray photoelectron, and Raman spectroscopies demonstrate uniform single‐layer growth of stoichiometric MoS2. The ability to reproducibly generate large‐area heterostructures is highly advantageous for both fundamental investigations and technological applications.  相似文献   

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Neuromorphic computing, which emulates the biological neural systems could overcome the high‐power consumption issue of conventional von‐Neumann computing. State‐of‐the‐art artificial synapses made of two‐terminal memristors, however, show variability in filament formation and limited capacity due to their inherent single presynaptic input design. Here, a memtransistor‐based arti?cial synapse is realized by integrating a memristor and selector transistor into a multiterminal device using monolayer polycrys‐talline‐MoS2 grown by a scalable chemical vapor deposition (CVD) process. Notably, the memtransistor offers both drain‐ and gate‐tunable nonvolatile memory functions, which efficiently emulates the long‐term potentiation/depression, spike‐amplitude, and spike‐timing‐dependent plasticity of biological synapses. Moreover, the gate tunability function that is not achievable in two‐terminal memristors, enables significant bipolar resistive states switching up to four orders‐of‐magnitude and high cycling endurance. First‐principles calculations reveal a new resistive switching mechanism driven by the diffusion of double sulfur vacancy perpendicular to the MoS2 grain boundary, leading to a conducting switching path without the need for a filament forming process. The seamless integration of multiterminal memtransistors may offer another degree‐of‐freedom to tune the synaptic plasticity by a third gate terminal for enabling complex neuromorphic learning.  相似文献   

10.
    
Organic–inorganic heterostructures are an emerging topic that is very interesting for optoelectronics. Here, non‐conventional p–n junctions are investigated using organic rubrene single crystal and 2D MoS2 as the p‐ and n‐type semiconducting materials, respectively. The current‐rectifying behavior is clearly observed in the junction device. The rectification ratio can be electrically tuned by the gate voltage due to the 2D nature of the heterostructure. The devices also show good photoresponse properties with a photoresponsivity of ≈500 mA W?1 and a fast response time. These findings suggest a new route to facilitate the design of nanoelectronic and optoelectronic devices based on layered inorganics and organics.  相似文献   

11.
单层或少数层MoS2是一种具有类石墨烯结构的新型二维层状化合物,拥有超薄的厚度、适宜的禁带宽度及独特的电学和光学性质,在场效应管、气体传感器、光探测器、锂电池和超电容等领域有广泛的应用价值.凭借其边缘悬挂键析氢催化活性高、比表面积大、抗光腐蚀性强等优点,二维MoS2在光催化应用上展现了良好的潜力.介绍了二维MoS2多样的晶体结构,分析了其能带可调、可见光吸收及催化析氢等特性,综述了二维MoS2从电催化析氢到光催化析氢的研究进展,并结合自身研究展望了单层MoS2作为直接光催化剂的潜在优势及其挑战.  相似文献   

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Recent studies indicate that synaptic scaling is a vital mechanism to solve instability risks brought by the positive feedback of synaptic weight change related with standalone Hebbian plasticity. There are two kinds of synaptic scaling in the neural network, including local scaling and global scaling, both important for stabilizing the neural function. In this paper, for the first time, local synaptic scaling is emulated based on the MoS2 neuristor. The first-principle calculation reveals that synaptic scaling achieved by the neuristor is associated with an internal residual Li+-related weak dynamical process. Experimental results show the potential of achieving global synaptic scaling by the same device. Moreover, inspired by the synaptic scaling in the human brain, a new method of weight mapping called weight scaling mapping (WSM) is proposed to improve the stability of an artificial neural network (ANN). The simulation results indicate that WSM can improve the accuracy and anti-noise ability of the network compared with the traditional mapping method. These findings provide new insight into bionic research and help advance the construction of stable neuromorphic systems.  相似文献   

13.
    
The investigation of two‐dimensional (2D) ferroelectrics has attracted significant interest in recent years for applications in functional electronics. Without the limitation of a finite size effect, 2D materials with stable layered structures and reduced surface energy may go beyond the presence of an enhanced depolarization field in ultrathin ferroelectrics, thereby opening a pathway to explore low‐dimensional ferroelectricity, making ultra‐high‐density devices possible and maintaining Moore's Law. Although many theoretical works on potential 2D ferroelectric materials have been conducted, much still needs to be accomplished experimentally, as it is rare for 2D ferroelectric materials to be proven and plenty of 2D ferroelectrics are waiting to be discovered. First, experimental and theoretical progress on 2D ferroelectric materials, including in‐plane and out‐of‐plane, is reviewed, followed by a general introduction to various characterization methods. Intrinsic mechanisms associated with promising 2D ferroelectric materials, together with related applications, are also discussed. Finally, an outlook for future trends and development in 2D ferroelectricity are explored. Researchers can use this to obtain a basic understanding of 2D ferroelectric materials and to build a database of progress of 2D ferroelectrics.  相似文献   

14.
Transition metal dichalcogenides layered nano-crystals are emerging as promising candidates for next-generation optoelectronic and quantum devices. In such systems, the interaction between excitonic states and atomic vibrations is crucial for many fundamental properties, such as carrier mobilities, quantum coherence loss, and heat dissipation. In particular, to fully exploit their valley-selective excitations, one has to understand the many-body exciton physics of zone-edge states. So far, theoretical and experimental studies have mainly focused on the exciton–phonon dynamics in high-energy direct excitons involving zone-center phonons. Here, ultrafast electron diffraction and ab initio calculations are used to investigate the many-body structural dynamics following nearly- resonant excitation of low-energy indirect excitons in MoS2. By exploiting the large momentum carried by scattered electrons, the excitation of in-plane K- and Q- phonon modes are identified with 𝑬′ symmetry as key for the stabilization of indirect excitons generated via near-infrared light at 1.55 eV, and light is shed on the role of phonon anharmonicity and the ensuing structural evolution of the MoS2 crystal lattice. The results highlight the strong selectivity of phononic excitations directly associated with the specific indirect- exciton nature of the wavelength-dependent electronic transitions triggered in the system.  相似文献   

15.
    
Solar steam generation is achieved by localized heating system using various floating photothermal materials. However, the steam generation efficiency is hindered by the difficulty in obtaining a photothermal material with ultrathin structure yet sufficient solar spectrum absorption capability. Herein, for the first time, an ultrathin 2D porous photothermal film based on MoS2 nanosheets and single‐walled nanotube (SWNT) films is prepared. The as‐prepared SWNT–MoS2 film exhibits an absorption of more than 82% over the whole solar spectrum range even with an ultrathin thickness of ≈120 nm. Moreover, the SWNT–MoS2 film floating on the water surface can generate a sharp temperature gradient due to the localized heat confinement effect. Meanwhile, the ultrathin and porous structure effectively facilitates the fast water vapor escaping, consequently an impressively high evaporation efficiency of 91.5% is achieved. Additionally, the superior mechanical strength of the SWNT–MoS2 film enables the film to be reused for atleast 20 solar illumination cycles and maintains stable water productivity as well as high salt rejection performance. This rational designed hybrid architecture provides a novel strategy for constructing 2D‐based nanomaterials for solar energy harvesting, chemical separation, and related technologies.  相似文献   

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17.
    
Semiconducting monolayers of transition metal dichalcogenides (TMDs) are considered as emergent materials for nanodevices and optoelectronic applications. The low‐frequency electrical noise of TMD‐based devices is much higher than Si and other conventional semiconductors. The reduction of this noise along with control of the Ohmic contact and carrier concentration of the such devices remain major challenges. Here, the low‐frequency (1/f) noise and transport properties of chemical‐vapor‐deposition‐grown MoS2 are presented. The high mobility of 20–40 cm2 V−1 s−1 of the monolayer devices is highly reproducible. Reliable methods to induce Ohmic contact and to tune carrier density over a wide range of 1011–1014 cm−2 are presented to study the fundamental mechanism of the 1/f noise. The noise performance in the high carrier concentration regime is explored for the first time with Ohmic contact of the devices and ideal sample quality. A significant reduction of the noise figure of merit is achievable in the high‐density regime. Polymer electrolyte encapsulation provides a practical method to effectively tune carrier density and engineer surface trap states of the monolayer TMDs, which would be helpful for practical applications of 2D atomic layers in nanoelectronics and photonics.  相似文献   

18.
    
Due to the novel optical and optoelectronic properties, 2D materials have received increasing interests for optoelectronics applications. Discovering new properties and functionalities of 2D materials is challenging yet promising. Here broadband polarization sensitive photodetectors based on few layer ReS2 are demonstrated. The transistor based on few layer ReS2 shows an n‐type behavior with the mobility of about 40 cm2 V?1 s?1 and on/off ratio of 105. The polarization dependence of photoresponse is ascribed to the unique anisotropic in‐plane crystal structure, consistent with the optical absorption anisotropy. The linear dichroic photodetection with a high photoresponsivity reported here demonstrates a route to exploit the intrinsic anisotropy of 2D materials and the possibility to open up new ways for the applications of 2D materials for light polarization detection.  相似文献   

19.
    
MoS2/montmorillonite (MoS2/MMT) composite nanosheets have been successfully synthesized by a facile hydrothermal method, and the catalytic activities of composites are evaluated by reduction reaction of methyl orange in aqueous phase. A preparation strategy demonstrates that MoS2 can be in situ formed on the surface of MMT from Na2MoO4· and H2NCSNH2. The microstructures and morphologies characterization indicates that few‐layered MoS2 nanosheets are uniformly grown on the surface of montmorillonite, and the hydrogen bonds are formed at the interfaces. The catalytic activity of MoS2/MMT is enhanced by support of montmorillonite, which can be attribu­ted to the large surface area, more reactive sites, dispersibility of MoS2/MMT, and the synergistic adsorption property of montmorillonite. Based on density functional theory calculations, the preferred adsorption configurations of MoS2 cluster on MMT are studied. The supporting effect of MMT on MoS2 nanoparticles will lead to the anchoring of these reactive MoS2 nanoparticles on clay surface and enhance the absorption ability of MoS2 to the organics and meanwhile improving the catalytic properties of the MoS2/MMT composite. The MoS2/MMT composite nanosheets show prospective application to treat effectively wastewater of dyes.  相似文献   

20.
    
Atomically thin 2D materials have drawn considerable attention in the past years with potential ranging from transistors to optoelectronics. As such, they are now foreseen as strong candidates for epitaxy-free technologies and the tetrad of size-weight-power-and-cost (SWAP-C) reduction. Targeting radiofrequency (RF) applications, the 2D semiconducting transition metal dichalcogenides (TMDC) family can offer the opportunity of wide tunability of their electronic properties, providing a large variety of band gaps. However, evaluation and integration of those materials into discrete components requires a stabilization of their properties. This work focuses on the evaluation of a large-scale compatible fabrication/passivation process on large area (>1000 µm2) monolayers of the prototypical 2D semiconductor MoS2. The process is developed including pre- and post-patterning protection/passivation layers. It is shown to reduce the initial natural p-doping of the sample, leading to lower transistor threshold voltages, a 106 ION/IOFF ratio, and an effective averaged field-effect mobility under ambient conditions of 20 cm2 V−1 s−1 (up to 35 cm2 V−1 s−1 for some devices), which represents an increase by a 40-fold factor compared to a conventional process carried on the large scale platform. This work represents an important step toward the integration of 2D TMDCs in discrete RF circuits and components.  相似文献   

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