High-performance field-effect transistors (FETs) based on atomically thin two-dimensional (2D) semiconductors have demonstrated great promise in post-Moore integrated circuits. However, unipolar p-type 2D semiconducto...
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High-performance field-effect transistors (FETs) based on atomically thin two-dimensional (2D) semiconductors have demonstrated great promise in post-Moore integrated circuits. However, unipolar p-type 2D semiconductor transistors yet remain challenging and suffer from low saturation current density (less than 10 µA·µm^(−1)) and high contact resistance (larger than 100 kΩ·µm), mainly limited by the Schottky barrier induced by the mismatch of the work-functions and the Fermi level pinning at the metal contact interfaces. Here, we overcome these two obstacles through van der Waals (vdW) integration of high work-function metal palladium (Pd) as the contacts onto monolayer WSe2 grown by chemical vapor deposition (CVD) method. We demonstrate unipolar p-type monolayer WSe2 FETs with superior device performance: room temperature on-state current density exceeding 100 µA·µm^(−1), contact resistance of 12 kΩ·µm, on/off ratio over 107, and field-effect hole mobility of ~ 103 cm2·V^(−1)·s^(−1). Electrical transport measurements reveal that the Fermi level pinning effect is completely effectively eliminated in monolayer WSe2 with vdW Pd contacts, leading to a Schottky barrier-free Ohmic contact at the metal-semiconductor junctions. Combining the advantages of large-scale vdW contact strategy and CVD growth, our results pave the way for wafer-scale fabrication of complementary-metal-oxide-semiconductor (CMOS) logic circuits based on atomically thin 2D semiconductors.
Chemical vapor deposition(CVD)has emerged as a promising approach for the controlled growth of graphene films with appealing scalability,controllability,and ***,the synthesis of high-quality graphene films still suffe...
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Chemical vapor deposition(CVD)has emerged as a promising approach for the controlled growth of graphene films with appealing scalability,controllability,and ***,the synthesis of high-quality graphene films still suffers from low production capacity and high energy consumption in the conventional hot-wall CVD *** contrast,owing to the different heating mode,cold-wall CVD(CW-CVD)system exhibits promising potential for the industrial-scale production,but the quality of as-received graphene remains inferior with limited domain size and high defect ***,we demonstrated an efficient method for the batch synthesis of high-quality graphene films with millimeter-sized domains based on CW-CVD *** reduced defect density and improved properties,the as-received graphene was proven to be promising candidate material for electronics and anti-corrosion *** study provides a new insight into the quality improvement of graphene derived from CW-CVD system,and paves a new avenue for the industrial production of high-quality graphene films for potential commercial applications.
This study presents a simple benchtop synthetic protocol for the fabrication of silver (Ag) nanostructures in aqueous media using environmentally friendly and inexpensive reagents under mild experimental conditions. N...
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In this study, we analyzed the properties of Bi4Ti3O12 microplates in the context of hydrogen evolution reaction. Piezoresponse force microscopy revealed a typical butterfly curve, indicating that as-synthesized Bi4Ti...
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Near-infrared(NIR)laser-induced phototherapy through NIR agents has demonstrated the great potential for cancer ***,insufficient tumor killing due to the nonuniform heat or cytotoxic singlet oxygen(1 O2)distribution o...
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Near-infrared(NIR)laser-induced phototherapy through NIR agents has demonstrated the great potential for cancer ***,insufficient tumor killing due to the nonuniform heat or cytotoxic singlet oxygen(1 O2)distribution over tumors from phototherapy results in tumor recurrence and inferior *** achieve high tumor killing efficacy,one of the solutions is to employ the combinational treatment of phototherapy with other modalities,especially with chemotherapeutic *** this paper,a simple and effective multimodal therapeutic system was designed via combining chemotherapy,photothermal therapy(PTT),and photodynamic therapy(PDT)to achieve the polytherapy of malignant glioma which is one of the most aggressive tumors in the ***-780(IR780)dye-labeled tube-forming peptoids(PepIR)were synthesized and self-assembled into crystalline nanotubes(PepIR nanotubes).These PepIR nanotubes showed an excellent efficacy for PDT/PTT because the IR780 photosensitizers were effectively packed and separated from each other within crystalline nanotubes by tuning IR780 density;thus,a self-quenching of these IR780 molecules was significantly ***,the efficient DOX loading achieved due to the nanotube large surface area contributed to an efficient and synergistic chemotherapy against glioma *** the unique properties of peptoids and peptoid nanotubes,we believe that the developed multimodal DOX-loaded PepIR nanotubes in this work offer great promises for future glioma therapy in clinic.
This study presents a superficial analysis of different wood polymer composites (WPC) comprising polystyrene (WPSC), poly(furfuryl alcohol) (WPFAC), and pine resin (WPRC) when exposed to artificial weathering. The stu...
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This article reviews the theory of fairness in AI-frommachine learning to federated learning,where the constraints on precision AI fairness and perspective solutions are also *** a reliable and quantitative evaluation...
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This article reviews the theory of fairness in AI-frommachine learning to federated learning,where the constraints on precision AI fairness and perspective solutions are also *** a reliable and quantitative evaluation of AI fairness,many associated concepts have been proposed,formulated and ***,the inexplicability of machine learning systems makes it almost impossible to include all necessary details in the modelling stage to ensure *** privacy worries induce the data unfairness and hence,the biases in the datasets for evaluating AI fairness are *** imbalance between algorithms’utility and humanization has further reinforced *** for federated learning systems,these constraints on precision AI fairness still *** solution is to reconcile the federated learning processes and reduce biases and imbalances accordingly.
Metamaterials are a class of materials with extraordinary capabilities derived from their engineered structure. In 2017, Frenzel et al. (science 358, 2017) conceptualized “three-dimensional mechanical metamaterials w...
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Metamaterials are a class of materials with extraordinary capabilities derived from their engineered structure. In 2017, Frenzel et al. (science 358, 2017) conceptualized “three-dimensional mechanical metamaterials with a twist,” which convert linear deformation into rotational motion—a mechanical response that surpasses the bounds of Cauchy continuum mechanics. However, the lack of suitable manufacturing technologies for producing metallic twist metamaterials has precluded their experimental validation and potential applications to date. Herein, 316L-stainless-steel twist metamaterials are fabricated at various scales using an emerging sintering-based technology—lithography metal manufacturing (LMM) —and their mechanical responses are tested using stereo digital image correlation. Results provide the first empirical evidence of compression-induced rotation in steel twist metamaterials and highlight their sensitivity to manufacturing defects. Download: Download video (753KB) Download: Download video (2MB) Download: Download video (4MB)
Lithography metal manufacturing (LMM) is an emerging sinter-based additive manufacturing (AM) technology for support-free 3D printing of extremely complex parts with micrometric resolution on a decimeter scale. Althou...
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Lithography metal manufacturing (LMM) is an emerging sinter-based additive manufacturing (AM) technology for support-free 3D printing of extremely complex parts with micrometric resolution on a decimeter scale. Although the printing phase of LMM is well-established, the sintering stage is challenging due to either high porosity or melting-induced deformation, particularly in thin-walled lattices and metamaterials. This study investigates the effects of sintering temperature on shape distortion, surface morphology, chemistry, porosity, microstructure, and mechanical properties of 316L stainless steel auxetic metamaterials 3D printed using LMM and sintered in a furnace customized for precise temperature control. Our results show that the fully dense grain microstructure with high plasticity can be sintering within 1300 – 1325 °C range. Going beyond this temperature results in shape distortion and embrittlement of the steel metamaterials. The previously recommended range of sintering temperatures for 316L steel, 1360 - 1380 °C need revision.
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