Single atom catalysts(SACs) possessing regulated electronic structure, high atom utilization, and superior catalytic efficiency have been studied in almost all fields in recent years. Carbon-based supporting SACs are ...Single atom catalysts(SACs) possessing regulated electronic structure, high atom utilization, and superior catalytic efficiency have been studied in almost all fields in recent years. Carbon-based supporting SACs are becoming popular materials because of their low cost, high electron conductivity, and controllable surface property. At the stage of catalysts preparation, the rational design of active sites is necessary for the substantial improvement of activity of catalysts. To date, the reported design strategies are mainly about synthesis mechanism and synthetic method. The level of understanding of design strategies of carbon-based single atom catalysts is requiring deep to be paved. The design strategies about manufacturing defects and coordination modulation of catalysts are presented. The design strategies are easy to carry out in the process of drawing up preparation routes. The components of carbon-based SACs can be divided into two parts: active site and carbon skeleton. In this review, the manufacture of defects and coordination modulation of two parts are introduced, respectively. The structure features and design strategies from the active sites and carbon skeletons to the overall catalysts are deeply discussed.Then, the structural design of different nano-carbon SACs is introduced systematically. The characterization of active site and carbon skeleton and the detailed mechanism of reaction process are summarized and analyzed. Next, the applications in the field of electrocatalysis for oxygen conversion and hydrogen conversion are illustrated. The relationships between the superior performance and the structure of active sites or carbon skeletons are discussed. Finally, the conclusion of this review and prospects on the abundant space for further promotion in broader fields are depicted. This review highlights the design and preparation thoughts from the parts to the whole. The detailed and systematic discussion will provide useful guidance for design of SACs for readers.展开更多
The rise of quantum computing has prompted the interest in the field of cryogenic electronics.Carbon-based materials hold great promise in the area of cryogenic electronics due to their excellent material properties a...The rise of quantum computing has prompted the interest in the field of cryogenic electronics.Carbon-based materials hold great promise in the area of cryogenic electronics due to their excellent material properties and emergent quantum effects.This paper introduces the advantages of carbon-based materials for cryogenic applications and reviews recent progress in carbon nanotubes and graphene for logic devices,sensors and novel quantum devices at cryogenic tempera-tures.Finally,the main challenges and extensive prospects for the fur-ther development of carbon-based cryoelectronics are summarized.展开更多
Spin properties of organic molecules have attracted great interest for their potential applications in spintronic devices and quantum computing.Fe-tetraphenyl porphyrin(Fe TPP)is of particular interest for its robust ...Spin properties of organic molecules have attracted great interest for their potential applications in spintronic devices and quantum computing.Fe-tetraphenyl porphyrin(Fe TPP)is of particular interest for its robust magnetic properties on metallic substrates.Fe TPP is prepared in vacuum via on-surface synthesis.Molecular structure and spin-related transport properties are characterized by low-temperature scanning tunneling microscope and spectroscopy at 0.5 K.Density functional theory calculations are performed to understand molecular adsorption and spin distribution on Au(111).The molecular structure of Fe TPP is distorted upon adsorption on the substrate.Spin excitations of Fe TPP are observed on the Fe atom and high pyrrole groups in differential conductance spectra.The calculated spin density distribution indicates that the electron spin of Fe TPP is mainly distributed on the Fe atom.The atomic transmission calculation indicates that electrons transport to substrate is mediated through Fe atom,when the tip is above the high pyrrole group.展开更多
Electrolysis of water splitting is a clean and sustainable method for hydrogen production without the consumption of fossil fuels or the emission of carbon dioxide.Although a series of non-precious metal catalysts hav...Electrolysis of water splitting is a clean and sustainable method for hydrogen production without the consumption of fossil fuels or the emission of carbon dioxide.Although a series of non-precious metal catalysts have been developed,they still cannot match the performance of precious metal catalysts in water electrolysis.Ruthenium(Ru),as a noble metal with an ideal cost-to-performance ratio and stable activity,is widely utilized by researchers.However,Ru-sites of electrocatalysts still face several challenges,such as size optimization,structural instability,and electronic structure regulation.This article reviews the design strategies on engineering Ru-based electrocatalysts for efficient water electrolysis,such as atomic-level dispersion,alloying,framework effect,doping,defect engineering,and interface design.And the application progress of precious metal catalysts in the seawater electrolysis was further reviewed and analyzed.These design strategies and their unique advantages provide a valuable theoretical foundation for the future application of Ru-based catalysts in hydrogen production via water electrolysis.展开更多
Surface with well-defined components and structures possesses unique electronic,magnetic,optical and chemical properties.As a result,surface chemistry research plays a crucial role in various fields such as catalysis,...Surface with well-defined components and structures possesses unique electronic,magnetic,optical and chemical properties.As a result,surface chemistry research plays a crucial role in various fields such as catalysis,energy,materials,quantum,and microelectronics.Surface science mainly investigates the correspondence between surface property and functionality.Scanning probe microscopy(SPM)techniques are important tools to characterize surface properties because of the capability of atomic-scale imaging,spectroscopy and manipulation at the single-atom level.In this review,we summarize recent advances in surface electronic,magnetic and optical properties characterized mainly by SPM-based methods.We focus on elucidating theπ-magnetism in graphene-based nanostructures,construction of spin qubits on surfaces,topology properties of surface organic structures,STM-based light emission,tip-enhanced Raman spectroscopy and integration of machine learning in SPM studies.展开更多
Large area,highly uniform,and density controllable carbon nanotube(CNT)films,either well-aligned or random network,are required for practical application of CNT-based electronics.Mass production methods for such CNT f...Large area,highly uniform,and density controllable carbon nanotube(CNT)films,either well-aligned or random network,are required for practical application of CNT-based electronics.Mass production methods for such CNT films and corresponding quality metrology,which are critical for pushing the CNT-based transistor technology to manufacturing,should be developed in advance.Much progress has been made on fabrication of CNT films;however,there still lacks a metrology for thoroughly quantifying their quality until now.In this paper,through comparing study of CNT films fabricated by dip-coating(DC)and direct deposition(DD)methods,local anisotropy in the film is revealed to impact the performance uniformity of devices so fabricated in a spatial scale dependent manner.The anisotropy effect should be taken into account for the quality characterization of CNT films,which was not noticed in previous studies.Based on these findings,we propose a four-parameter metrology to quantify the overall quality of the CNT films,which includes the local tube density(DL),global density uniformity(Cv),local degree of order(OL),and the relative tube proportion in a certain orientation(Pθ)at a location.The four-parameter characterization and corresponding device performance confirm DC films are superior to DD films for practical application.The four-parameter metrology is not only powerful for overall quality evaluation of CNT films,but also able to predict the fluctuation of devices’performance.Therefore,this material metrology is important for devices and circuits design and valuable for pushing the CNT-based transistor technology forward.展开更多
Geometries of molecule-molecule interfaces strongly influence the current passing from one molecule to another. The contact conductance of molecule-molecule junctions which consist of fullerene and tin phthalocyanine ...Geometries of molecule-molecule interfaces strongly influence the current passing from one molecule to another. The contact conductance of molecule-molecule junctions which consist of fullerene and tin phthalocyanine molecules is investigated with a low-temperature scanning tunneling microscope. Two types of molecules are deposited onto Cu(111). Fullerene molecules are transferred to tips through controlled contact of STM tips on molecules. The molecule-molecule junctions are formed by approaching fullereneterminated tips to tin phthalocyanine molecules on Cu(111). Our experimental method can be extended to study the intermolecular charge transport of a range of molecular junctions.展开更多
Carbon nanotube field-effect transistors(CNTFETs)are increasingly recognized as a viable option for creating high-performance,low-power,and densely integrated circuits(ICs).Advancements in carbon-based electronics,enc...Carbon nanotube field-effect transistors(CNTFETs)are increasingly recognized as a viable option for creating high-performance,low-power,and densely integrated circuits(ICs).Advancements in carbon-based electronics,encompassing materials and device technology,have enabled the fabrication of circuits with over 1000 gates,marking carbon-based integrated circuit design as a burgeoning field of research.A critical challenge in the realm of carbon-based very-large-scale integration(VLSI)is the lack of suitable automated design methodologies and infrastructure platforms.In this study,we present the development of a waferscale 3μm carbon-based complementary metal-oxide-semiconductor(CMOS)process design kit(PDK)(3μm-CNTFETs-PDK)compatible with silicon-based Electronic Design Automation(EDA)tools and VLSI circuit design flow.The proposed 3μm-CNTFETs-PDK features a contacted gate pitch(CGP)of 21μm,a gate density of 128 gates/mm^(2),and a transistor density of 554 transistors/mm^(2),with an intrinsic gate delay around 134 ns.Validation of the 3μm-CNTFETs-PDK was achieved through the successful design and tape-out of 153 standard cells and 333-stage ring oscillator circuits.Leveraging the carbon-based PDK and a silicon-based design platform,we successfully implemented a complete 64-bit static random-access memory(SRAM)circuit system for the first time,which exhibited timing,power,and area characteristics of clock@10 kHz,122.1μW,3795μm×2810μm.This research confirms that carbon-based IC design can be compatible with existing EDA tools and silicon-based VLSI design flow,thereby laying the groundwork for future carbon-based VLSI advancements.展开更多
Superconducting wire-networks are paradigms to study Cooper pairing issues,vortex dynamics and arrangements.Recently,emergent low-dimensional crystalline superconductors were reported in the minimal-disorder limit,pro...Superconducting wire-networks are paradigms to study Cooper pairing issues,vortex dynamics and arrangements.Recently,emergent low-dimensional crystalline superconductors were reported in the minimal-disorder limit,providing novel platforms to reveal vortices-related physics.Study on superconducting loops with high-crystallinity is thus currently demanded.Here,we report fabrication and transport measurement of finite square-network based on two-dimensional crystalline superconductor Mo_(2)C.We observe oscillations in the resistance as a function of the magnetic flux through the loops.Resistance dips at both matching field and fractional fillings are revealed.Temperature and current evolutions are carried out in magnetoresistance to study vortex dynamics.The amplitude of oscillation is enhanced due to the interaction between thermally activated vortices and the currents induced in the loops.The driving current reduces the effective activation energy for vortex,giving rise to stronger vortex interaction.Moreover,by the thermally activated vortex creep model,we derive the effective potential barrier for vortex dissipation,which shows well-defined correspondence with structures in magnetoresistance.Our work shows that low-dimensional crystalline superconducting network based on Mo_(2)C possesses pronounced potential in studying the modulation of vortex arrangements and dynamics,paving the way for further investigations on crystalline superconducting network with various configurations.展开更多
Surface chemistry focuses on the investigation of the adsorption,migration,assembly,activation,reaction,and desorption of atoms and molecules at surfaces.Surface chemistry plays the pivotal roles in both fundamental s...Surface chemistry focuses on the investigation of the adsorption,migration,assembly,activation,reaction,and desorption of atoms and molecules at surfaces.Surface chemistry plays the pivotal roles in both fundamental science and applied technology.This review will summarize the recent progresses on surface assembly,synthesis and catalysis investigated mainly by scanning tunneling microscopy and atomic force microscopy.Surface assemblies of water and small biomolecules,construction of Sierpin′ski triangles and surface chirality are summarized.On-surface synthesis of conjugated carbo-and heterocycles and other kinds of carbon nanostructures are surveyed.Surface model catalysis,including single-atom catalysis and electrochemical catalysis,are discussed at the single-atom level.展开更多
Photodetectors are the fundamental building blocks for many optoelectronic systems,including night vision,optical communications,biomedical imaging,security and motion detection.Carbon nanotubes(CNTs),which have a dir...Photodetectors are the fundamental building blocks for many optoelectronic systems,including night vision,optical communications,biomedical imaging,security and motion detection.Carbon nanotubes(CNTs),which have a direct-bandgap structure,a broad spectral response and a large absorption coefficient,provide an ideal research platform for the exploration of high-performance infrared photodetectors.In the past twenty years,great efforts have been devoted to improve detection sensitivity via adopting high-purity CNT films,various doping strategies,optical manipulations and sensitizing nanostructures.Despite considerable strides made,challenges remain in simultaneously achieving high responsivity,low dark current and fast response.In this Review,we summarize recent advances on key device construction strategies and underlying concepts that contribute to improve performance of fabricated CNT photodetectors.The newly emerging heterojunction gated CNT transistors and their potential are highlighted to overcome trade-offs between the optical and electronic processes.Novel applications of CNT photodetectors are further summarized for advanced optoelectronic technologies.展开更多
Due to its remarkable electrical and optical capabilities,optoelectronic devices based on the semiconducting single-walled carbon nanotube(s-SWCNT)have been studied extensively in the last two decades.First,s-SWCNT is...Due to its remarkable electrical and optical capabilities,optoelectronic devices based on the semiconducting single-walled carbon nanotube(s-SWCNT)have been studied extensively in the last two decades.First,s-SWCNT is a direct bandgap semiconductor with a high infrared absorption coefficient and high electron/hole mobility.In addition,as a typical one-dimensional material,there is no lattice mismatch between s-SWCNT and any substrates.Another advantage is that the optoelectronic devices of s-SWCNT can be processed at low temperatures.s-SWCNT has intriguing potential and applications in solar cells,light-emitting diodes(LEDs),photodetectors,and three-dimensional(3D)optoelectronic integration.In recent years,along with the advancement of solution purification technology,the high-purity s-SWCNTs film has laid the foundation for constructing large-area,homogenous,and high-performance optoelectronic devices.In this review,optoelectronic devices based on s-SWCNTs film and related topics are reviewed,including the preparation of high purity s-SWCNTs film,the progress of photodetectors based on the s-SWCNTs film,and challenges of s-SWCNTs film photodetectors.展开更多
Embedding metal clusters in surface-supported metal-organic frameworks gives rise to multinuclear metal-organic coordination structures(MMOCs).The controllable configurations,exposed clusters,and multilevel interactio...Embedding metal clusters in surface-supported metal-organic frameworks gives rise to multinuclear metal-organic coordination structures(MMOCs).The controllable configurations,exposed clusters,and multilevel interactions of MMOCs imply numerous potential applications,such as in catalysis,light-energy conversion,spintronics,and molecular electronics.Thus,the fabrication of MMOCs has been investigated extensively.According to the formation mechanism of metal clusters,we summarize five types of MMOCs.Attractive properties,e.g.,magnetism,charge transfer and chirality,emerge in these systems.The surface-supported feature enables researchers to detect these properties via surface-sensitive techniques,such as scanning tunneling microscopy/spectroscopy,X-ray photoelectron spectroscopy,noncontact atomic force microscopy and local contact potential difference measurement.In addition,the results obtained from density functional theory calculations can be mutually verified with experiments.These studies pave the way for further applications of MMOCs.展开更多
Interactions between molecules and surfaces are crucial in modern surface science.In particular,surfaces catalyze molecular reactions and modulate molecular spin states.In this article,we investigate the adsorption be...Interactions between molecules and surfaces are crucial in modern surface science.In particular,surfaces catalyze molecular reactions and modulate molecular spin states.In this article,we investigate the adsorption behaviors and electronic structures of chloro-iron phthalocyanine(ClFePc)on Au(111).Combining ultrahigh vacuum scanning tunneling microscopy experiments with density functional theory calculations,we found indications of surface-catalyzed dechlorination.Our findings reveal that the adsorption behavior of ClFePc is determined by its adsorption direction.ClFePc in the Cl-up(Cl pointing to the vacuum)configuration exhibits stable adsorption on the Au(111)surface.Conversely,the Cl-down(Cl pointing to the substrate)configuration is unstable,resulting in the dissociation of the Cl–Fe bond due to interactions with the Au(111)surface.Through scanning tunneling spectroscopy analysis,we further investigate the Kondo resonance features and spin characteristics.Notably,following dechlorination,the spin-state transitions from S=3/2 to 1.This study provides profound insights into the surface-molecule interaction and its application in modulating magnetic properties.展开更多
Bilayer transition-metal dichalcogenides(TMDCs)are promising channel materials for state-of-the-art transistors,due to their smaller bandgap,higher carrier mobility,and better electrostatic control than those of the m...Bilayer transition-metal dichalcogenides(TMDCs)are promising channel materials for state-of-the-art transistors,due to their smaller bandgap,higher carrier mobility,and better electrostatic control than those of the monolayer counterparts.Epitaxial growth and controllable doping of wafer-scale bilayer TMDCs single crystals are two pivotal tasks to meet the practical applications of high-performance electronic devices.Despite considerable efforts have been made,addressing such fundamental issues simultaneously has yet to be realized.Here we design an ingenious Fe-assisted epitaxial strategy to synthesize centimeter-size uniform bilayer tungsten disulfide(WS_(2))with unidirectional alignment on industry-compatible c-plane sapphire.The introduction of Fe promotes the formation of parallel steps on sapphire surfaces to induce the edge-nucleation of unidirectionally aligned bilayer WS_(2)and the evolution of centimeter-size uniform films.The ionic liquid gated transistors with ultrahigh electron mobility(169 cm^(2)·V^(-1)·s^(-1))and remarkable on/off current ratio(10^(8))are constructed based on the centimeter-size bilayer Fe-WS_(2),due to the reduction of Schottky barrier width induced by Fe doping.This work provides a simple and general approach for synthesizing and doping of wafer-scale bilayer TMDCs,which should accelerate the further device downscaling to extend Moore’s law.展开更多
Bound states in the continuum(BICs)have gained considerable attention for their ability to strengthen light-matter interactions,enabling applications in lasing,sensing,and imaging.These properties also show great prom...Bound states in the continuum(BICs)have gained considerable attention for their ability to strengthen light-matter interactions,enabling applications in lasing,sensing,and imaging.These properties also show great promise for intensifying free-electron radiation.Recently,researchers realized momentum-mismatch-driven quasi-BICs in compound grating waveguides.This category of quasi-BICs exhibits high Q factors over a broad frequency spectrum.In this paper,we explore the possibility of achieving multi-frequency terahertz Smith-Purcell radiation empowered by momentum-mismatch-driven quasi-BICs in silicon compound grating waveguides.By leveraging the low-loss properties of silicon in the terahertz range,quasi-BICs are achieved through guided-mode resonance,delivering exceptionally high Q factors over a broad frequency spectrum.The broadband nature of these quasi-BICs enables efficient energy extraction from electron beams across varying voltages,while their multimode characteristics support simultaneous interactions with multiple modes,further boosting radiation intensity.The findings demonstrate significant enhancement of free-electron radiation at multiple frequencies,addressing the limitations of narrowband methods and high-loss metallic systems.By integrating broadband performance with the advantages of low-loss dielectric platforms,this work advances the development of compact,tunable terahertz free-electron radiation sources and provides valuable insights into optimizing quasi-BIC systems for practical applications.展开更多
Carbon nanotube field-effect transistors(CNT FETs)have been demonstrated to exhibit high performance only through low-temperature fabrication process and require a low thermal budget to construct monolithic three-dime...Carbon nanotube field-effect transistors(CNT FETs)have been demonstrated to exhibit high performance only through low-temperature fabrication process and require a low thermal budget to construct monolithic three-dimensional(M3D)integrated circuits(ICs),which have been considered a promising tech-nology to meet the demands of high-bandwidth computing and fully func-tional integration.However,the lack of high-quality CNT materials at the upper layer and a low-parasitic interlayer dielectric(ILD)makes the reported M3D CNT FETs and ICs unable to provide the predicted high performance.In this work,we demonstrate a multilayer stackable process for M3D integration of high-performance aligned carbon nanotube(A-CNT)transistors and ICs.A low-κ(-3)interlayer SiO_(2)layer is prepared from spin-on-glass(SOG)through processes with a highest temperature of 220℃,presenting low parasitic capaci-tance between two transistor layers and excellent planarization to offer an ideal surface for the A-CNT and device fabrication process.A high-quality A-CNT film with a carrier mobility of 650 cm 2 V^(-1)s^(-1)is prepared on the ILD layer through a clean transfer process,enabling the upper CNT FETs fabri-cated with a low-temperature process to exhibit high on-state current(1 mAμm^(-1))and peak transconductance(0.98 mSμm^(-1)).The bottom A-CNT FETs maintain pristine high performance after undergoing the ILD growth and upper FET fabrication.As a result,5-stage ring oscillators utilizing the M3D architecture show a gate propagation delay of 17 ps and an active region of approximately 100μm 2,representing the fastest and the most compact M3D ICs to date.展开更多
Thanks to its single-atomic-layer structure,high carrier transport,and low power dissipation,carbon nanotube electronics is a leading candidate towards beyond-silicon technologies.Its low temperature fabrication proce...Thanks to its single-atomic-layer structure,high carrier transport,and low power dissipation,carbon nanotube electronics is a leading candidate towards beyond-silicon technologies.Its low temperature fabrication processes enable three-dimensional(3D)integration with logic and memory(static random access memory(SRAM),magnetic random access memory(MRAM),resistive random access memory(RRAM),etc.)to realize efficient near-memory computing.Importantly,carbon nanotube transistors require good thermal stability up to 400℃ processing temperature to be compatible with back-end-of-line(BEOL)process,which has not been previously addressed.In this work,we developed a robust wafer-scale process to build complementary carbon nanotube transistors with high thermal stability and good uniformity,where AlN was employed as electrostatic doping layer.The gate stack and passivation layer were optimized to realize high-quality interfaces.Specifically,we demonstrate 1-bit carbon nanotube full adders working under 250℃ with rail-to-rail outputs.展开更多
Brain-inspired neuromorphic computing is expected for breaking through the bottleneck of the computer of conventional von Neumann architecture. To this end, the first step is to mimic functions of biological neurons a...Brain-inspired neuromorphic computing is expected for breaking through the bottleneck of the computer of conventional von Neumann architecture. To this end, the first step is to mimic functions of biological neurons and synapses by electronic devices. In this paper, synaptic transistors were fabricated by using carbon nanotube (CNT) thin films and interface charge trapping effects were confirmed to dominate the weight update of the synaptic transistors. Large synaptic weight update was realized due to the high sensitivity of the CNTs to the trapped charges in vicinity. Basic synaptic functions including inhibitory post-synaptic current (IPSC), excitatory post-synaptic current (EPSC), spike-timing-dependent plasticity (STDP), and paired-pulse facilitation (PPF) were mimicked. Large dynamic range of STDP (> 2,180) and low power consumption per spike (∼ 0.7 pJ) were achieved. By taking advantage of the long retention time of the trapped charges and uniform device-to-device performance, long-term image memory behavior of neural network was successfully imitated in a CNT synaptic transistor array.展开更多
Semiconducting single-walled carbon nanotubes(s-SWCNTs)are fascinating materials for future electronic and optical applications.Conjugated polymer wrapping is one of the most promising methods for mass production of h...Semiconducting single-walled carbon nanotubes(s-SWCNTs)are fascinating materials for future electronic and optical applications.Conjugated polymer wrapping is one of the most promising methods for mass production of high purity s-SWCNTs.However,its chiral selectivity is relatively inferior to other s-SWCNT production methods.In this paper,the chiral selectivity of two polymers,poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(6,6′-{2,2′-bipyridine})](PFO-BPy)and poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl](PCz),which are representatives of widely used polyfluorene and polycarbazole families,respectively,were comparatively studied.Both polymers exhibited high selectivity for a subset of existing chiral species in each of the commercially available raw SWCNT materials(CoMoCAT,HiPco,and arc-discharge)which cover a diameter range of 0.6–1.8 nm.Less chiral species were selected by PFO-BPy from small diameter(<1 nm)raw SWCNT materials,while more from large diameter(>1.2 nm)raw materials.High chiral purity(6,5)(>99%)and(7,5)(>75%)solutions were extracted by PFO-BPy and PCz from CoMoCAT materials,respectively.The different chiral angle and diameter selections for different raw materials by both polymers were ascribed to their different geometrical structures and related polymer-tube interactions.Our work provides indispensable information for better understanding the mechanism of polymer wrapping method and improving extraction of single chirality sSWCNTs.展开更多
基金funded by the National Natural Science Foundation of China (Nos. 22279118, 31901272, 21401168, U1204203)National Science Fund for Distinguished Young of China (No. 22225202)+1 种基金Young Top Talent Program of Zhongyuan-YingcaiJihua (No. 30602674)Top-Notch Talent Program of Henan Agricultural University (No. 30501034)。
文摘Single atom catalysts(SACs) possessing regulated electronic structure, high atom utilization, and superior catalytic efficiency have been studied in almost all fields in recent years. Carbon-based supporting SACs are becoming popular materials because of their low cost, high electron conductivity, and controllable surface property. At the stage of catalysts preparation, the rational design of active sites is necessary for the substantial improvement of activity of catalysts. To date, the reported design strategies are mainly about synthesis mechanism and synthetic method. The level of understanding of design strategies of carbon-based single atom catalysts is requiring deep to be paved. The design strategies about manufacturing defects and coordination modulation of catalysts are presented. The design strategies are easy to carry out in the process of drawing up preparation routes. The components of carbon-based SACs can be divided into two parts: active site and carbon skeleton. In this review, the manufacture of defects and coordination modulation of two parts are introduced, respectively. The structure features and design strategies from the active sites and carbon skeletons to the overall catalysts are deeply discussed.Then, the structural design of different nano-carbon SACs is introduced systematically. The characterization of active site and carbon skeleton and the detailed mechanism of reaction process are summarized and analyzed. Next, the applications in the field of electrocatalysis for oxygen conversion and hydrogen conversion are illustrated. The relationships between the superior performance and the structure of active sites or carbon skeletons are discussed. Finally, the conclusion of this review and prospects on the abundant space for further promotion in broader fields are depicted. This review highlights the design and preparation thoughts from the parts to the whole. The detailed and systematic discussion will provide useful guidance for design of SACs for readers.
基金supported by the National Key Research&Develop-ment Program(Grant No.2022YFB4401601)Natural Science Foundation of China(62225101,12374035 and 11974026).
文摘The rise of quantum computing has prompted the interest in the field of cryogenic electronics.Carbon-based materials hold great promise in the area of cryogenic electronics due to their excellent material properties and emergent quantum effects.This paper introduces the advantages of carbon-based materials for cryogenic applications and reviews recent progress in carbon nanotubes and graphene for logic devices,sensors and novel quantum devices at cryogenic tempera-tures.Finally,the main challenges and extensive prospects for the fur-ther development of carbon-based cryoelectronics are summarized.
基金supported by the Ministry of Science and Technology(Nos.2017YFA0205003,2018YFA0306003)National Natural Science Foundation of China(Nos.21991132,21972002,21902003,21673118,21972067)。
文摘Spin properties of organic molecules have attracted great interest for their potential applications in spintronic devices and quantum computing.Fe-tetraphenyl porphyrin(Fe TPP)is of particular interest for its robust magnetic properties on metallic substrates.Fe TPP is prepared in vacuum via on-surface synthesis.Molecular structure and spin-related transport properties are characterized by low-temperature scanning tunneling microscope and spectroscopy at 0.5 K.Density functional theory calculations are performed to understand molecular adsorption and spin distribution on Au(111).The molecular structure of Fe TPP is distorted upon adsorption on the substrate.Spin excitations of Fe TPP are observed on the Fe atom and high pyrrole groups in differential conductance spectra.The calculated spin density distribution indicates that the electron spin of Fe TPP is mainly distributed on the Fe atom.The atomic transmission calculation indicates that electrons transport to substrate is mediated through Fe atom,when the tip is above the high pyrrole group.
基金supported by the National Natural Science Foundation of China(No.22279118)the National Science Fund for Distinguished Young of China(No.22225202)+1 种基金the Special Projects of Henan Province Key Research and Development and Promotion(Science and Technology Research)(No.232102241033)the Young Top Talent Program of Zhongyuan-Yingcai-Jihua(No.30602674).
文摘Electrolysis of water splitting is a clean and sustainable method for hydrogen production without the consumption of fossil fuels or the emission of carbon dioxide.Although a series of non-precious metal catalysts have been developed,they still cannot match the performance of precious metal catalysts in water electrolysis.Ruthenium(Ru),as a noble metal with an ideal cost-to-performance ratio and stable activity,is widely utilized by researchers.However,Ru-sites of electrocatalysts still face several challenges,such as size optimization,structural instability,and electronic structure regulation.This article reviews the design strategies on engineering Ru-based electrocatalysts for efficient water electrolysis,such as atomic-level dispersion,alloying,framework effect,doping,defect engineering,and interface design.And the application progress of precious metal catalysts in the seawater electrolysis was further reviewed and analyzed.These design strategies and their unique advantages provide a valuable theoretical foundation for the future application of Ru-based catalysts in hydrogen production via water electrolysis.
文摘Surface with well-defined components and structures possesses unique electronic,magnetic,optical and chemical properties.As a result,surface chemistry research plays a crucial role in various fields such as catalysis,energy,materials,quantum,and microelectronics.Surface science mainly investigates the correspondence between surface property and functionality.Scanning probe microscopy(SPM)techniques are important tools to characterize surface properties because of the capability of atomic-scale imaging,spectroscopy and manipulation at the single-atom level.In this review,we summarize recent advances in surface electronic,magnetic and optical properties characterized mainly by SPM-based methods.We focus on elucidating theπ-magnetism in graphene-based nanostructures,construction of spin qubits on surfaces,topology properties of surface organic structures,STM-based light emission,tip-enhanced Raman spectroscopy and integration of machine learning in SPM studies.
基金This work was supported by the National Key Research and Development Program(No.2016YFA0201902)the National Natural Science Foundation of China(Nos.61621061 and 51991341)+1 种基金Instrument Function Development Innovation Program of Chinese Academy of Sciences(No.282019000057)the Special Program of Beijing Municipal Science&Technology Commission(Nos.Z181100000118002 and Z181100003818001).
文摘Large area,highly uniform,and density controllable carbon nanotube(CNT)films,either well-aligned or random network,are required for practical application of CNT-based electronics.Mass production methods for such CNT films and corresponding quality metrology,which are critical for pushing the CNT-based transistor technology to manufacturing,should be developed in advance.Much progress has been made on fabrication of CNT films;however,there still lacks a metrology for thoroughly quantifying their quality until now.In this paper,through comparing study of CNT films fabricated by dip-coating(DC)and direct deposition(DD)methods,local anisotropy in the film is revealed to impact the performance uniformity of devices so fabricated in a spatial scale dependent manner.The anisotropy effect should be taken into account for the quality characterization of CNT films,which was not noticed in previous studies.Based on these findings,we propose a four-parameter metrology to quantify the overall quality of the CNT films,which includes the local tube density(DL),global density uniformity(Cv),local degree of order(OL),and the relative tube proportion in a certain orientation(Pθ)at a location.The four-parameter characterization and corresponding device performance confirm DC films are superior to DD films for practical application.The four-parameter metrology is not only powerful for overall quality evaluation of CNT films,but also able to predict the fluctuation of devices’performance.Therefore,this material metrology is important for devices and circuits design and valuable for pushing the CNT-based transistor technology forward.
基金supported by the Ministry of Science and Technology (Nos.2018YFA0306003,2017YFA0205003)National Natural Science Foundation of China (Nos.21972002,21902003)supported by High-performance Computing Platform of Peking University。
文摘Geometries of molecule-molecule interfaces strongly influence the current passing from one molecule to another. The contact conductance of molecule-molecule junctions which consist of fullerene and tin phthalocyanine molecules is investigated with a low-temperature scanning tunneling microscope. Two types of molecules are deposited onto Cu(111). Fullerene molecules are transferred to tips through controlled contact of STM tips on molecules. The molecule-molecule junctions are formed by approaching fullereneterminated tips to tin phthalocyanine molecules on Cu(111). Our experimental method can be extended to study the intermolecular charge transport of a range of molecular junctions.
基金The authors gratefully acknowledge fundings from the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(No.XDA0330401)CAS Youth Interdisciplinary Team(No.JCTD-2022-07).
文摘Carbon nanotube field-effect transistors(CNTFETs)are increasingly recognized as a viable option for creating high-performance,low-power,and densely integrated circuits(ICs).Advancements in carbon-based electronics,encompassing materials and device technology,have enabled the fabrication of circuits with over 1000 gates,marking carbon-based integrated circuit design as a burgeoning field of research.A critical challenge in the realm of carbon-based very-large-scale integration(VLSI)is the lack of suitable automated design methodologies and infrastructure platforms.In this study,we present the development of a waferscale 3μm carbon-based complementary metal-oxide-semiconductor(CMOS)process design kit(PDK)(3μm-CNTFETs-PDK)compatible with silicon-based Electronic Design Automation(EDA)tools and VLSI circuit design flow.The proposed 3μm-CNTFETs-PDK features a contacted gate pitch(CGP)of 21μm,a gate density of 128 gates/mm^(2),and a transistor density of 554 transistors/mm^(2),with an intrinsic gate delay around 134 ns.Validation of the 3μm-CNTFETs-PDK was achieved through the successful design and tape-out of 153 standard cells and 333-stage ring oscillator circuits.Leveraging the carbon-based PDK and a silicon-based design platform,we successfully implemented a complete 64-bit static random-access memory(SRAM)circuit system for the first time,which exhibited timing,power,and area characteristics of clock@10 kHz,122.1μW,3795μm×2810μm.This research confirms that carbon-based IC design can be compatible with existing EDA tools and silicon-based VLSI design flow,thereby laying the groundwork for future carbon-based VLSI advancements.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974026,11774005,and 51802314)the National Key Research and Development Program of China(Grant No.2017YFA0303304)+1 种基金Science Foundation of Jihua Laboratory(Grant No.2021B0301030003-03)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000)。
文摘Superconducting wire-networks are paradigms to study Cooper pairing issues,vortex dynamics and arrangements.Recently,emergent low-dimensional crystalline superconductors were reported in the minimal-disorder limit,providing novel platforms to reveal vortices-related physics.Study on superconducting loops with high-crystallinity is thus currently demanded.Here,we report fabrication and transport measurement of finite square-network based on two-dimensional crystalline superconductor Mo_(2)C.We observe oscillations in the resistance as a function of the magnetic flux through the loops.Resistance dips at both matching field and fractional fillings are revealed.Temperature and current evolutions are carried out in magnetoresistance to study vortex dynamics.The amplitude of oscillation is enhanced due to the interaction between thermally activated vortices and the currents induced in the loops.The driving current reduces the effective activation energy for vortex,giving rise to stronger vortex interaction.Moreover,by the thermally activated vortex creep model,we derive the effective potential barrier for vortex dissipation,which shows well-defined correspondence with structures in magnetoresistance.Our work shows that low-dimensional crystalline superconducting network based on Mo_(2)C possesses pronounced potential in studying the modulation of vortex arrangements and dynamics,paving the way for further investigations on crystalline superconducting network with various configurations.
基金supported by the National Natural Science Foundation of China(Nos.22225202,92356309,22132007,21991132,22172002)。
文摘Surface chemistry focuses on the investigation of the adsorption,migration,assembly,activation,reaction,and desorption of atoms and molecules at surfaces.Surface chemistry plays the pivotal roles in both fundamental science and applied technology.This review will summarize the recent progresses on surface assembly,synthesis and catalysis investigated mainly by scanning tunneling microscopy and atomic force microscopy.Surface assemblies of water and small biomolecules,construction of Sierpin′ski triangles and surface chirality are summarized.On-surface synthesis of conjugated carbo-and heterocycles and other kinds of carbon nanostructures are surveyed.Surface model catalysis,including single-atom catalysis and electrochemical catalysis,are discussed at the single-atom level.
基金supported by National Science Foundation of China(U21A6004,62225101 and 62101008).
文摘Photodetectors are the fundamental building blocks for many optoelectronic systems,including night vision,optical communications,biomedical imaging,security and motion detection.Carbon nanotubes(CNTs),which have a direct-bandgap structure,a broad spectral response and a large absorption coefficient,provide an ideal research platform for the exploration of high-performance infrared photodetectors.In the past twenty years,great efforts have been devoted to improve detection sensitivity via adopting high-purity CNT films,various doping strategies,optical manipulations and sensitizing nanostructures.Despite considerable strides made,challenges remain in simultaneously achieving high responsivity,low dark current and fast response.In this Review,we summarize recent advances on key device construction strategies and underlying concepts that contribute to improve performance of fabricated CNT photodetectors.The newly emerging heterojunction gated CNT transistors and their potential are highlighted to overcome trade-offs between the optical and electronic processes.Novel applications of CNT photodetectors are further summarized for advanced optoelectronic technologies.
基金This work was supported by the National Key Research&Development Program(No.2020YFA0714703)National Science Foundation of China(Nos.62071008 and U21A6004)Ji Hua Laboratory(No.2021B0301030003).
文摘Due to its remarkable electrical and optical capabilities,optoelectronic devices based on the semiconducting single-walled carbon nanotube(s-SWCNT)have been studied extensively in the last two decades.First,s-SWCNT is a direct bandgap semiconductor with a high infrared absorption coefficient and high electron/hole mobility.In addition,as a typical one-dimensional material,there is no lattice mismatch between s-SWCNT and any substrates.Another advantage is that the optoelectronic devices of s-SWCNT can be processed at low temperatures.s-SWCNT has intriguing potential and applications in solar cells,light-emitting diodes(LEDs),photodetectors,and three-dimensional(3D)optoelectronic integration.In recent years,along with the advancement of solution purification technology,the high-purity s-SWCNTs film has laid the foundation for constructing large-area,homogenous,and high-performance optoelectronic devices.In this review,optoelectronic devices based on s-SWCNTs film and related topics are reviewed,including the preparation of high purity s-SWCNTs film,the progress of photodetectors based on the s-SWCNTs film,and challenges of s-SWCNTs film photodetectors.
基金supported by the Ministry of Science and Technology(2018YFA0306003)National Natural Science Foundation of China(22225202,22132007,21991132,21972002,22172002,21972067).
文摘Embedding metal clusters in surface-supported metal-organic frameworks gives rise to multinuclear metal-organic coordination structures(MMOCs).The controllable configurations,exposed clusters,and multilevel interactions of MMOCs imply numerous potential applications,such as in catalysis,light-energy conversion,spintronics,and molecular electronics.Thus,the fabrication of MMOCs has been investigated extensively.According to the formation mechanism of metal clusters,we summarize five types of MMOCs.Attractive properties,e.g.,magnetism,charge transfer and chirality,emerge in these systems.The surface-supported feature enables researchers to detect these properties via surface-sensitive techniques,such as scanning tunneling microscopy/spectroscopy,X-ray photoelectron spectroscopy,noncontact atomic force microscopy and local contact potential difference measurement.In addition,the results obtained from density functional theory calculations can be mutually verified with experiments.These studies pave the way for further applications of MMOCs.
基金supported by the National Natural Science Foundation of China(grant nos.22225202,92356309,22132007,21991132,and 22172002).
文摘Interactions between molecules and surfaces are crucial in modern surface science.In particular,surfaces catalyze molecular reactions and modulate molecular spin states.In this article,we investigate the adsorption behaviors and electronic structures of chloro-iron phthalocyanine(ClFePc)on Au(111).Combining ultrahigh vacuum scanning tunneling microscopy experiments with density functional theory calculations,we found indications of surface-catalyzed dechlorination.Our findings reveal that the adsorption behavior of ClFePc is determined by its adsorption direction.ClFePc in the Cl-up(Cl pointing to the vacuum)configuration exhibits stable adsorption on the Au(111)surface.Conversely,the Cl-down(Cl pointing to the substrate)configuration is unstable,resulting in the dissociation of the Cl–Fe bond due to interactions with the Au(111)surface.Through scanning tunneling spectroscopy analysis,we further investigate the Kondo resonance features and spin characteristics.Notably,following dechlorination,the spin-state transitions from S=3/2 to 1.This study provides profound insights into the surface-molecule interaction and its application in modulating magnetic properties.
基金supported by the National Key R&D Program of China(No.2021YFA1200800)the National Natural Science Foundation of China(Nos.U24A2055, 92164103)+2 种基金the Natural Science Foundation of Hubei Province(No.2024AFA052)Wuhan Science and Technology Bureau(Knowledge Innovation Program of Wuhan-Basic Research,No.2023010201010067)the Fundamental Research Funds for the Central Universities(No.2042023kf0187)。
文摘Bilayer transition-metal dichalcogenides(TMDCs)are promising channel materials for state-of-the-art transistors,due to their smaller bandgap,higher carrier mobility,and better electrostatic control than those of the monolayer counterparts.Epitaxial growth and controllable doping of wafer-scale bilayer TMDCs single crystals are two pivotal tasks to meet the practical applications of high-performance electronic devices.Despite considerable efforts have been made,addressing such fundamental issues simultaneously has yet to be realized.Here we design an ingenious Fe-assisted epitaxial strategy to synthesize centimeter-size uniform bilayer tungsten disulfide(WS_(2))with unidirectional alignment on industry-compatible c-plane sapphire.The introduction of Fe promotes the formation of parallel steps on sapphire surfaces to induce the edge-nucleation of unidirectionally aligned bilayer WS_(2)and the evolution of centimeter-size uniform films.The ionic liquid gated transistors with ultrahigh electron mobility(169 cm^(2)·V^(-1)·s^(-1))and remarkable on/off current ratio(10^(8))are constructed based on the centimeter-size bilayer Fe-WS_(2),due to the reduction of Schottky barrier width induced by Fe doping.This work provides a simple and general approach for synthesizing and doping of wafer-scale bilayer TMDCs,which should accelerate the further device downscaling to extend Moore’s law.
基金National Natural Science Foundation of China(62271011,U21A20458)National Key R&D Program of China(2021YFA1600302)Beijing Science Foundation for Distinguished Young Scholars(JQ21011)。
文摘Bound states in the continuum(BICs)have gained considerable attention for their ability to strengthen light-matter interactions,enabling applications in lasing,sensing,and imaging.These properties also show great promise for intensifying free-electron radiation.Recently,researchers realized momentum-mismatch-driven quasi-BICs in compound grating waveguides.This category of quasi-BICs exhibits high Q factors over a broad frequency spectrum.In this paper,we explore the possibility of achieving multi-frequency terahertz Smith-Purcell radiation empowered by momentum-mismatch-driven quasi-BICs in silicon compound grating waveguides.By leveraging the low-loss properties of silicon in the terahertz range,quasi-BICs are achieved through guided-mode resonance,delivering exceptionally high Q factors over a broad frequency spectrum.The broadband nature of these quasi-BICs enables efficient energy extraction from electron beams across varying voltages,while their multimode characteristics support simultaneous interactions with multiple modes,further boosting radiation intensity.The findings demonstrate significant enhancement of free-electron radiation at multiple frequencies,addressing the limitations of narrowband methods and high-loss metallic systems.By integrating broadband performance with the advantages of low-loss dielectric platforms,this work advances the development of compact,tunable terahertz free-electron radiation sources and provides valuable insights into optimizing quasi-BIC systems for practical applications.
基金National Key Research&Development Program,Grant/Award Number:2022YFB4401601Natural Science Foundation of China,Grant/Award Number:62225101Beijing Municipal Science and Technology Commission,Grant/Award Number:Z191100007019001-3。
文摘Carbon nanotube field-effect transistors(CNT FETs)have been demonstrated to exhibit high performance only through low-temperature fabrication process and require a low thermal budget to construct monolithic three-dimensional(M3D)integrated circuits(ICs),which have been considered a promising tech-nology to meet the demands of high-bandwidth computing and fully func-tional integration.However,the lack of high-quality CNT materials at the upper layer and a low-parasitic interlayer dielectric(ILD)makes the reported M3D CNT FETs and ICs unable to provide the predicted high performance.In this work,we demonstrate a multilayer stackable process for M3D integration of high-performance aligned carbon nanotube(A-CNT)transistors and ICs.A low-κ(-3)interlayer SiO_(2)layer is prepared from spin-on-glass(SOG)through processes with a highest temperature of 220℃,presenting low parasitic capaci-tance between two transistor layers and excellent planarization to offer an ideal surface for the A-CNT and device fabrication process.A high-quality A-CNT film with a carrier mobility of 650 cm 2 V^(-1)s^(-1)is prepared on the ILD layer through a clean transfer process,enabling the upper CNT FETs fabri-cated with a low-temperature process to exhibit high on-state current(1 mAμm^(-1))and peak transconductance(0.98 mSμm^(-1)).The bottom A-CNT FETs maintain pristine high performance after undergoing the ILD growth and upper FET fabrication.As a result,5-stage ring oscillators utilizing the M3D architecture show a gate propagation delay of 17 ps and an active region of approximately 100μm 2,representing the fastest and the most compact M3D ICs to date.
基金the National Natural Science Foundation of China(No.61888102)the Beijing Municipal Science and Technology Commission(No.D171100006617002).
文摘Thanks to its single-atomic-layer structure,high carrier transport,and low power dissipation,carbon nanotube electronics is a leading candidate towards beyond-silicon technologies.Its low temperature fabrication processes enable three-dimensional(3D)integration with logic and memory(static random access memory(SRAM),magnetic random access memory(MRAM),resistive random access memory(RRAM),etc.)to realize efficient near-memory computing.Importantly,carbon nanotube transistors require good thermal stability up to 400℃ processing temperature to be compatible with back-end-of-line(BEOL)process,which has not been previously addressed.In this work,we developed a robust wafer-scale process to build complementary carbon nanotube transistors with high thermal stability and good uniformity,where AlN was employed as electrostatic doping layer.The gate stack and passivation layer were optimized to realize high-quality interfaces.Specifically,we demonstrate 1-bit carbon nanotube full adders working under 250℃ with rail-to-rail outputs.
基金This work was supported by the National Key Research and Development Program (No. 2016YFA0201902)the National Natural Science Foundation of China (No. 51991341)the Open Research Fund of Key Laboratory of Space Utilization, and Chinese Academy of Sciences (No. LSU-KFJJ-2020-06).
文摘Brain-inspired neuromorphic computing is expected for breaking through the bottleneck of the computer of conventional von Neumann architecture. To this end, the first step is to mimic functions of biological neurons and synapses by electronic devices. In this paper, synaptic transistors were fabricated by using carbon nanotube (CNT) thin films and interface charge trapping effects were confirmed to dominate the weight update of the synaptic transistors. Large synaptic weight update was realized due to the high sensitivity of the CNTs to the trapped charges in vicinity. Basic synaptic functions including inhibitory post-synaptic current (IPSC), excitatory post-synaptic current (EPSC), spike-timing-dependent plasticity (STDP), and paired-pulse facilitation (PPF) were mimicked. Large dynamic range of STDP (> 2,180) and low power consumption per spike (∼ 0.7 pJ) were achieved. By taking advantage of the long retention time of the trapped charges and uniform device-to-device performance, long-term image memory behavior of neural network was successfully imitated in a CNT synaptic transistor array.
基金the National Natural Science Foundation of China(Nos.U21A6004 and 51991341)Science and Technology Major Project of Shanxi(No.202101030201022)Young Talents Program of Beijing(No.2018000020028G349)。
文摘Semiconducting single-walled carbon nanotubes(s-SWCNTs)are fascinating materials for future electronic and optical applications.Conjugated polymer wrapping is one of the most promising methods for mass production of high purity s-SWCNTs.However,its chiral selectivity is relatively inferior to other s-SWCNT production methods.In this paper,the chiral selectivity of two polymers,poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(6,6′-{2,2′-bipyridine})](PFO-BPy)and poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl](PCz),which are representatives of widely used polyfluorene and polycarbazole families,respectively,were comparatively studied.Both polymers exhibited high selectivity for a subset of existing chiral species in each of the commercially available raw SWCNT materials(CoMoCAT,HiPco,and arc-discharge)which cover a diameter range of 0.6–1.8 nm.Less chiral species were selected by PFO-BPy from small diameter(<1 nm)raw SWCNT materials,while more from large diameter(>1.2 nm)raw materials.High chiral purity(6,5)(>99%)and(7,5)(>75%)solutions were extracted by PFO-BPy and PCz from CoMoCAT materials,respectively.The different chiral angle and diameter selections for different raw materials by both polymers were ascribed to their different geometrical structures and related polymer-tube interactions.Our work provides indispensable information for better understanding the mechanism of polymer wrapping method and improving extraction of single chirality sSWCNTs.
