With a large number of researches being conducted on two?dimen?sional(2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of...With a large number of researches being conducted on two?dimen?sional(2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of combining distinct functional 2D materials into heterostructures naturally emerged that pro?vides unprecedented platforms for exploring new physics that are not accessible in a single 2D material or 3D heterostructures. Along with the rapid development of controllable, scalable, and programmed synthesis techniques of high?quality 2D heterostructures, various heterostructure devices with extraordinary performance have been designed and fabricated, including tunneling transistors, photodetectors, and spintronic devices. In this review, we present a summary of the latest progresses in fabrications, properties, and applications of di erent types of 2D heterostruc?tures, followed by the discussions on present challenges and perspectives of further investigations.展开更多
Wafer-scale van der Waals heterostructures(vdWHs),benefitting from the rich diversity in materials available and stacking geometry,precise controllability in devices structure and performance,and unprecedented potenti...Wafer-scale van der Waals heterostructures(vdWHs),benefitting from the rich diversity in materials available and stacking geometry,precise controllability in devices structure and performance,and unprecedented potential in practical application,have attracted considerable attention in the field of twodimensional(2D)materials.This article reviews the state-of-the-art research activities that focus on wafer-scale vdWHs and their(opto)electronic applications.We begin with the preparation strategies of vdWHs with wafer size and illustrate them from four key aspects,that is,mechanical-assembly stack,successive deposition,synchronous evolution,and seeded growth.We discuss the fundamental principle,underlying mechanism,advantages,and disadvantages for each strategy.We will then review the applications of large-area vdWHs based devices in electronic,optoelectronic and flexible devices field,unveiling their promising potential for practical application.Ultimately,we will demonstrate the challenges they face and provide some viable solutions on waferscale heterostructure synthesis and device fabrication.展开更多
Nanomaterial shapes can have profound effects on material properties, and therefore offer an efficient way to improve the performances of designed materials and devices. The rational fabrication of multidimensional ar...Nanomaterial shapes can have profound effects on material properties, and therefore offer an efficient way to improve the performances of designed materials and devices. The rational fabrication of multidimensional architectures such as one dimensional （1D）-two dimensional （2D） hybrid nanomaterials can integrate the merits of individual components and provide enhanced functionality. However, it is still very challenging to fabricate 1D/2D architectures because of the different growth mechanisms of the nanostructures. Here, we present a new solvent- mediated, surface reaction-driven growth route for synthesis of CdS nanowire （NW）/CdIn2S4 nanosheet （NS） 1D/2D architectures. The as-obtained CdS NW/ CdIn2S4 NS structures exhibit much higher visible-light-responsive photocatalytic activities for water splitting than the individual components. The CdS NW/CdIn2S4 NS heterostructure was further fabricated into photoelectrodes, which achieved a considerable photocurrent density of 2.85 mA·cm^-2 at 0 V vs. the reversible hydrogen electrode （RHE） without use of any co-catalysts. This represents one of the best results from a CdS-based photoelectrochemical （PEC） cell. Both the multidimensional nature and type II band alignment of the 1D/2D CdS/CdIn2S4 heterostructure contribute to the enhanced photocatalyfic and photoelectrochemical activity. The present work not only provides a new strategy for designing multidimensional 1D/2D heterostructures, but also documents the development of highly efficient energy conversion catalysts.展开更多
Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existi...Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existing tunneling heterostructures are mainly operated in the visible wavelengths and have been rarely investigated for the nearinfrared detection.Herein,we report the design and realization of a novel broken-gap tunneling heterostructure by combining WSe2 and Bi2Se3,which is able to realize the simultaneous visible and near-infrared detection because of the complementary bandgaps of WSe2 and Bi2Se3(1.46 and 0.3 e V respectively).Thanks to the realigned band structure,the heterostructure shows an ultralow dark current below picoampere and a high tunneling-dominated photocurrent.The photodetector based on our tunneling heterostructure exhibits a superior specific detectivity of 7.9×1012Jones for a visible incident of 532 nm and 2.2×1010Jones for a 1456 nm nearinfrared illumination.Our study demonstrates a new band structure engineering avenue for the construction of van der Waals tunneling heterostructures for high-performance wide band photodetection.展开更多
Monodisperse and size-tunable magnetic iron oxide nanoparticles （NPs） have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of...Monodisperse and size-tunable magnetic iron oxide nanoparticles （NPs） have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of the as-synthesized iron oxide NPs decrease with increasing concentrations of iron oleate complex and oleic acid/oleylamine. In addition, the size-dependent crystallinity and magnetic properties of iron oxide NPs are presented. It is found that larger iron oxide NPs have a higher degree of crystallinity and saturation magnetization. More importantly, various M-iron oxide heterostructures （M = Au, Ag, Pt, Pd） have been successfully fabricated by using the same synthesis procedure. The iron oxide NPs are grown over the pre-made metal seeds through a seed-mediated growth process. The physicochemical properties of Au-Fe3O4 heterostructures have been characterized by X-ray diffraction （XRD）, superconducting quantum interference device （SQUID） magnetometry and UV-vis spectroscopy. The as-synthesized Au-Fe3O4 heterostructures show a red-shift in surface plasmon resonance peak compared with Au NPs and similar magnetic properties to Fe3O4 NPs. The heterojunction effects present in such nanostructures offer the opportunity to tune the irphysicochemical properties. Therefore, this synthesis process can be regarded as an efficient way to fabricate a series of heterostructures for a variety of applications.展开更多
Van der Waals(vdW)heterostructures provide a unique opportunity to develop various electronic and optoelectronic devices with specific functions by designing novel device structures,especially for bioinspired neuromor...Van der Waals(vdW)heterostructures provide a unique opportunity to develop various electronic and optoelectronic devices with specific functions by designing novel device structures,especially for bioinspired neuromorphic optoelectronic devices,which require the integration of nonvolatile memory and excellent optical responses.Here,we demonstrate a programmable optoelectronic synaptic floating-gate transistor based on multilayer graphene/h-BN/MoS2 vdW heterostructures,where both plasticity emulation and modulation were successfully realized in a single device.The dynamic tunneling process of photogenerated carriers through the as-fabricated vdW heterostructures contributed to a large memory ratio(105)between program and erase states.Our device can work as a functional or silent synapse by applying a program/erase voltage spike as a modulatory signal to determine the response to light stimulation,leading to a programmable operation in optoelectronic synaptic transistors.Moreover,an ultra-low energy consumption per light spike event(~2.5 fJ)was obtained in the program state owing to a suppressed noise current by program operation in our floating-gate transistor.This study proposes a feasible strategy to improve the functions of optoelectronic synaptic devices with ultra-low energy consumption based on vdW heterostructures designed for highly efficient artificial neural networks.展开更多
Planar micro-supercapacitors （MSCs） have drawn extensive research attention owing to their unique structural design and size compatibility for microelectronic devices. Graphene has been widely used to improve the pe...Planar micro-supercapacitors （MSCs） have drawn extensive research attention owing to their unique structural design and size compatibility for microelectronic devices. Graphene has been widely used to improve the performance of microscale electrochemical capacitors. However, investigations of an intrinsic electrochemical mechanism for graphene-based microscale devices are still not sufficient. Here, micro-supercapacitors with various typical architectures are fabricated as models to study the graphene effect, and their electrochemical performance is also evaluated. The results show that ionic accessibility and adsorption are greatly improved after the introduction of the holey graphene intermediate layer. This study provides a new route to understand intrinsic electrochemical behaviors and possesses exciting potential for highly efficient on-chip micro-energy storage.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)with fascinating electronic energy band structures,rich valley physical properties and strong spin–orbit coupling have attracted tremendous interest,and show g...Two-dimensional(2D)transition metal dichalcogenides(TMDs)with fascinating electronic energy band structures,rich valley physical properties and strong spin–orbit coupling have attracted tremendous interest,and show great potential in electronic,optoelectronic,spintronic and valleytronic fields.Stacking 2D TMDs have provided unprecedented opportunities for constructing artificial functional structures.Due to the low cost,high yield and industrial compatibility,chemical vapor deposition(CVD)is regarded as one of the most promising growth strategies to obtain high-quality and large-area 2D TMDs and heterostructures.Here,state-of-the-art strategies for preparing TMDs details of growth control and related heterostructures construction via CVD method are reviewed and discussed,including wafer-scale synthesis,phase transition,doping,alloy and stacking engineering.Meanwhile,recent progress on the application of multi-functional devices is highlighted based on 2D TMDs.Finally,challenges and prospects are proposed for the practical device applications of 2D TMDs.展开更多
Two-dimensional(2D) transition metal carbides, carbonitrides and nitrides, known as MXenes, are emerging quickly at the frontiers of 2D materials world. Their exotic properties such as the highest electrical conductiv...Two-dimensional(2D) transition metal carbides, carbonitrides and nitrides, known as MXenes, are emerging quickly at the frontiers of 2D materials world. Their exotic properties such as the highest electrical conductivity among all solution-processed 2 D materials, the best electromagnetic interference shielding performance outperforming that of copper or aluminum at a nanoscale thickness, as well as the highest volumetric capacitance for pseudocapacitors, have been attracting extensive fundamental research and applications. Their unique surface chemistries, that is, hydrophilic groups terminated on the surface of MXenes after etching and delamination, enable plenty of opportunities for assembling into MXene building blocks. Particularly, assembling at liquid–liquid, liquid–solid, liquid–air, and solid–solid interfaces allows the efficient fabrication of various structures, including MXene surfactants, MXene heterostructures, MXene transparent films. Interfacial assembly of MXenes is of significance in unveiling more versatilities of MXenes as well as impacts on novel MXene-based architectures, based on which enhanced performance of devices is achieved. As such, this review focuses on the interfacial assembly of MXenes, explaining mechanisms behind various assembling and providing classical examples for corresponding interfacial assembling techniques. Applications of these as-assembled architectures are also discussed in brief. We believe this review may shed light on the interfacial chemistry of MXenes, thus guiding more efficient fabrication of MXene-based functional films/coatings/electrodes/devices.展开更多
Bi_(2)Te_(3)-based materials are not only the most important and widely used room temperature thermoelectric(TE)materials but are also canonical examples of topological insulators in which the topological surface stat...Bi_(2)Te_(3)-based materials are not only the most important and widely used room temperature thermoelectric(TE)materials but are also canonical examples of topological insulators in which the topological surface states are protected by the time-reversal symmetry.High-performance thin films based on Bi_(2)Te_(3)- have attracted worldwide attention during the past two decades due primarily to their outstanding TE performance as highly efficient TE coolers and as miniature and flexible TE power generators for a variety of electronic devices.Moreover,intriguing topological phenomena,such as the quantum anomalous Hall effect and topological superconductivity discovered in Bi_(2)Te_(3)-based thin films and heterostructures,have shaped research directions in the field of condensed matter physics.In Bi_(2)Te_(3)-based films and heterostructures,delicate control of the carrier transport,film composition,and microstructure are prerequisites for successful device operations as well as for experimental verification of exotic topological phenomena.This review summarizes the recent progress made in atomic defect engineering,carrier tuning,and band engineering down to a nanoscale regime and how it relates to the growth and fabrication of high-quality Bi_(2)Te_(3)-based films.The review also briefly discusses the physical insight into the exciting field of topological phenomena that were so dramatically realized in Bi_(2)Te_(3)-and Bi_(2)Se_(3)‐based structures.It is expected that Bi_(2)Te_(3)-based thin films and heterostructures will play an ever more prominent role as flexible TE devices collecting and converting low-level(body)heat into electricity for numerous electronic applications.It is also likely that such films will continue to be a remarkable platform for the realization of novel topological phenomena.展开更多
The ever-growing market demands for lithium ion batteries have stimulated numerous research efforts aiming at the exploration of novel electrode materials with higher capacity and long-term cycling stability.Two-dimen...The ever-growing market demands for lithium ion batteries have stimulated numerous research efforts aiming at the exploration of novel electrode materials with higher capacity and long-term cycling stability.Two-dimensional (2D)nanomaterials and their heterostructures are an intense area of study and promise great potential in electrochemical lithium storage owing to their unique properties that result from structural planar confinement.Here we report a microwave chemistry strategy to integrate ultrathin SnO2 nanosheets into graphene layer to construct surface-to-surface 2D heterostructured architectures,which can provide unique structural planar confinement for highly reversible electrochemical lithium storage.The as-synthesized 2D SnO2/graphene heterostructures can exhibit high reversible capacity of 688.5mAh g^-1 over 500cycles with excellent long-term cycling stability and good rate capability when used as anode materials for lithium ion batteries.The present work definitely reveals the advantages of 2D heterostructures featured with a surface-to-surface stack between two different nanosheets in energy storage and conversion devices.展开更多
We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. O...We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron area/density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron＇s, the spin-splitting states of the polaron are more stable than electron＇s.展开更多
2D materials including graphene and TMDs have proven interesting physical properties and promising optoelectronic applications.We reviewed the growth,characterization and optoelectronics based on 2D TMDs and their het...2D materials including graphene and TMDs have proven interesting physical properties and promising optoelectronic applications.We reviewed the growth,characterization and optoelectronics based on 2D TMDs and their heterostructures,and demonstrated their unique and high quality of performances.For example,we observed the large mobility,fast response and high photo-responsivity in Mo S;,WS;and WSe;phototransistors,as well as the novel performances in vd W heterostructures such as the strong interlayer coupling,am-bipolar and rectifying behaviour,and the obvious photovoltaic effect.It is being possible that 2D family materials could play an increasingly important role in the future nano- and opto-electronics,more even than traditional semiconductors such as silicon.展开更多
基金supported by NSF of China (Grant No. 61775241)partly by the Innovation-driven Project (Grant No. 2017CX019)the funding support from the Australian Research Council (ARC Discovery Projects, DP180102976)
文摘With a large number of researches being conducted on two?dimen?sional(2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of combining distinct functional 2D materials into heterostructures naturally emerged that pro?vides unprecedented platforms for exploring new physics that are not accessible in a single 2D material or 3D heterostructures. Along with the rapid development of controllable, scalable, and programmed synthesis techniques of high?quality 2D heterostructures, various heterostructure devices with extraordinary performance have been designed and fabricated, including tunneling transistors, photodetectors, and spintronic devices. In this review, we present a summary of the latest progresses in fabrications, properties, and applications of di erent types of 2D heterostruc?tures, followed by the discussions on present challenges and perspectives of further investigations.
基金National Nature Science Foundation of China,Grant/Award Number:21825103Natural Science Foundation of Hubei Province of China,Grant/Award Number:2019CFA002Fundamental Research Funds for the Central University,Grant/Award Number:2019kfyXMBZ018。
文摘Wafer-scale van der Waals heterostructures(vdWHs),benefitting from the rich diversity in materials available and stacking geometry,precise controllability in devices structure and performance,and unprecedented potential in practical application,have attracted considerable attention in the field of twodimensional(2D)materials.This article reviews the state-of-the-art research activities that focus on wafer-scale vdWHs and their(opto)electronic applications.We begin with the preparation strategies of vdWHs with wafer size and illustrate them from four key aspects,that is,mechanical-assembly stack,successive deposition,synchronous evolution,and seeded growth.We discuss the fundamental principle,underlying mechanism,advantages,and disadvantages for each strategy.We will then review the applications of large-area vdWHs based devices in electronic,optoelectronic and flexible devices field,unveiling their promising potential for practical application.Ultimately,we will demonstrate the challenges they face and provide some viable solutions on waferscale heterostructure synthesis and device fabrication.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 51372173, 21673160, and 51420105002）, Natural Science Foundation of Zhejiang for Distinguished Young Scholars （No. LR16B010002）, Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure （No. SKL201409SIC）, and startup funds of Syracuse University.
文摘Nanomaterial shapes can have profound effects on material properties, and therefore offer an efficient way to improve the performances of designed materials and devices. The rational fabrication of multidimensional architectures such as one dimensional （1D）-two dimensional （2D） hybrid nanomaterials can integrate the merits of individual components and provide enhanced functionality. However, it is still very challenging to fabricate 1D/2D architectures because of the different growth mechanisms of the nanostructures. Here, we present a new solvent- mediated, surface reaction-driven growth route for synthesis of CdS nanowire （NW）/CdIn2S4 nanosheet （NS） 1D/2D architectures. The as-obtained CdS NW/ CdIn2S4 NS structures exhibit much higher visible-light-responsive photocatalytic activities for water splitting than the individual components. The CdS NW/CdIn2S4 NS heterostructure was further fabricated into photoelectrodes, which achieved a considerable photocurrent density of 2.85 mA·cm^-2 at 0 V vs. the reversible hydrogen electrode （RHE） without use of any co-catalysts. This represents one of the best results from a CdS-based photoelectrochemical （PEC） cell. Both the multidimensional nature and type II band alignment of the 1D/2D CdS/CdIn2S4 heterostructure contribute to the enhanced photocatalyfic and photoelectrochemical activity. The present work not only provides a new strategy for designing multidimensional 1D/2D heterostructures, but also documents the development of highly efficient energy conversion catalysts.
基金supported by the National Nature Science Foundation of China(21825103 and 51727809)Hubei Provincial Natural Science Foundation of China(2019CFA002)the Fundamental Research Funds for the Central Universities(2019kfyXMBZ018)。
文摘Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existing tunneling heterostructures are mainly operated in the visible wavelengths and have been rarely investigated for the nearinfrared detection.Herein,we report the design and realization of a novel broken-gap tunneling heterostructure by combining WSe2 and Bi2Se3,which is able to realize the simultaneous visible and near-infrared detection because of the complementary bandgaps of WSe2 and Bi2Se3(1.46 and 0.3 e V respectively).Thanks to the realigned band structure,the heterostructure shows an ultralow dark current below picoampere and a high tunneling-dominated photocurrent.The photodetector based on our tunneling heterostructure exhibits a superior specific detectivity of 7.9×1012Jones for a visible incident of 532 nm and 2.2×1010Jones for a 1456 nm nearinfrared illumination.Our study demonstrates a new band structure engineering avenue for the construction of van der Waals tunneling heterostructures for high-performance wide band photodetection.
文摘Monodisperse and size-tunable magnetic iron oxide nanoparticles （NPs） have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of the as-synthesized iron oxide NPs decrease with increasing concentrations of iron oleate complex and oleic acid/oleylamine. In addition, the size-dependent crystallinity and magnetic properties of iron oxide NPs are presented. It is found that larger iron oxide NPs have a higher degree of crystallinity and saturation magnetization. More importantly, various M-iron oxide heterostructures （M = Au, Ag, Pt, Pd） have been successfully fabricated by using the same synthesis procedure. The iron oxide NPs are grown over the pre-made metal seeds through a seed-mediated growth process. The physicochemical properties of Au-Fe3O4 heterostructures have been characterized by X-ray diffraction （XRD）, superconducting quantum interference device （SQUID） magnetometry and UV-vis spectroscopy. The as-synthesized Au-Fe3O4 heterostructures show a red-shift in surface plasmon resonance peak compared with Au NPs and similar magnetic properties to Fe3O4 NPs. The heterojunction effects present in such nanostructures offer the opportunity to tune the irphysicochemical properties. Therefore, this synthesis process can be regarded as an efficient way to fabricate a series of heterostructures for a variety of applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:62104017,52072204,62074015National Postdoctoral Program for Innovative Talents of China,Grant/Award Number:BX20200049China Postdoctoral Science Foundation,Grant/Award Number:2021M690013。
文摘Van der Waals(vdW)heterostructures provide a unique opportunity to develop various electronic and optoelectronic devices with specific functions by designing novel device structures,especially for bioinspired neuromorphic optoelectronic devices,which require the integration of nonvolatile memory and excellent optical responses.Here,we demonstrate a programmable optoelectronic synaptic floating-gate transistor based on multilayer graphene/h-BN/MoS2 vdW heterostructures,where both plasticity emulation and modulation were successfully realized in a single device.The dynamic tunneling process of photogenerated carriers through the as-fabricated vdW heterostructures contributed to a large memory ratio(105)between program and erase states.Our device can work as a functional or silent synapse by applying a program/erase voltage spike as a modulatory signal to determine the response to light stimulation,leading to a programmable operation in optoelectronic synaptic transistors.Moreover,an ultra-low energy consumption per light spike event(~2.5 fJ)was obtained in the program state owing to a suppressed noise current by program operation in our floating-gate transistor.This study proposes a feasible strategy to improve the functions of optoelectronic synaptic devices with ultra-low energy consumption based on vdW heterostructures designed for highly efficient artificial neural networks.
基金This work was supported by the National Basic Research Program of China （Nos. 2013CB934103 and 2012CB933003）, the International Science ＆ Technology Cooperation Program of China （No. 2013DFA50840）, the National Natural Science Foundation of China （Nos. 51522001 and 51272197）, the National Science Fund for Hubei Provincial Natural Science Young Scholars （No. 51425204）, the Hubei Science Fund for Distinguished Young Scholars （No. 2014CFA035）, the Fundamental Research Funds for the Central Universities （WUT： 2015-PY-2, 2015-CL-A1-03）. We are deeply thankful to Prof. Charles M. Lieber of Harvard University, Prof. Dongyuan Zhao of Fudan University, and Prof. Jun Liu of Pacific Northwest National Laboratory for their stimulating discussion and kind help.
文摘Planar micro-supercapacitors （MSCs） have drawn extensive research attention owing to their unique structural design and size compatibility for microelectronic devices. Graphene has been widely used to improve the performance of microscale electrochemical capacitors. However, investigations of an intrinsic electrochemical mechanism for graphene-based microscale devices are still not sufficient. Here, micro-supercapacitors with various typical architectures are fabricated as models to study the graphene effect, and their electrochemical performance is also evaluated. The results show that ionic accessibility and adsorption are greatly improved after the introduction of the holey graphene intermediate layer. This study provides a new route to understand intrinsic electrochemical behaviors and possesses exciting potential for highly efficient on-chip micro-energy storage.
基金supported by the National Key R&D Program of China(No.2018YFA0703700,J.H.)the National Natural Science Foundation of China(Nos.91964203,J.H.,62004142,Y.W.,62134001,62104171,R.C.,62104172,L.Y.,62174122,Y.G.and 11774269,S.Y.)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB44000000,J.H.)the Natural Science Foundation of Hubei Province,China(Nos.2021CFB037,R.C.and 2020CFA041,S.Y.)the Fundamental Research Funds for the Central Universities(No.2042021kf0067,R.C.)the Special Fund of Hubei Luojia Laboratory.
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)with fascinating electronic energy band structures,rich valley physical properties and strong spin–orbit coupling have attracted tremendous interest,and show great potential in electronic,optoelectronic,spintronic and valleytronic fields.Stacking 2D TMDs have provided unprecedented opportunities for constructing artificial functional structures.Due to the low cost,high yield and industrial compatibility,chemical vapor deposition(CVD)is regarded as one of the most promising growth strategies to obtain high-quality and large-area 2D TMDs and heterostructures.Here,state-of-the-art strategies for preparing TMDs details of growth control and related heterostructures construction via CVD method are reviewed and discussed,including wafer-scale synthesis,phase transition,doping,alloy and stacking engineering.Meanwhile,recent progress on the application of multi-functional devices is highlighted based on 2D TMDs.Finally,challenges and prospects are proposed for the practical device applications of 2D TMDs.
文摘Two-dimensional(2D) transition metal carbides, carbonitrides and nitrides, known as MXenes, are emerging quickly at the frontiers of 2D materials world. Their exotic properties such as the highest electrical conductivity among all solution-processed 2 D materials, the best electromagnetic interference shielding performance outperforming that of copper or aluminum at a nanoscale thickness, as well as the highest volumetric capacitance for pseudocapacitors, have been attracting extensive fundamental research and applications. Their unique surface chemistries, that is, hydrophilic groups terminated on the surface of MXenes after etching and delamination, enable plenty of opportunities for assembling into MXene building blocks. Particularly, assembling at liquid–liquid, liquid–solid, liquid–air, and solid–solid interfaces allows the efficient fabrication of various structures, including MXene surfactants, MXene heterostructures, MXene transparent films. Interfacial assembly of MXenes is of significance in unveiling more versatilities of MXenes as well as impacts on novel MXene-based architectures, based on which enhanced performance of devices is achieved. As such, this review focuses on the interfacial assembly of MXenes, explaining mechanisms behind various assembling and providing classical examples for corresponding interfacial assembling techniques. Applications of these as-assembled architectures are also discussed in brief. We believe this review may shed light on the interfacial chemistry of MXenes, thus guiding more efficient fabrication of MXene-based functional films/coatings/electrodes/devices.
基金This study was supported by the Natural Science Foun-dation of China(Grant No.51632006,51521001 and 91963120)National Key Research and Development Program of China(Grant No.2019YFA0704900)Wuhan Frontier Project on Applied Research Foundation(Grant No.2019010701011405).
文摘Bi_(2)Te_(3)-based materials are not only the most important and widely used room temperature thermoelectric(TE)materials but are also canonical examples of topological insulators in which the topological surface states are protected by the time-reversal symmetry.High-performance thin films based on Bi_(2)Te_(3)- have attracted worldwide attention during the past two decades due primarily to their outstanding TE performance as highly efficient TE coolers and as miniature and flexible TE power generators for a variety of electronic devices.Moreover,intriguing topological phenomena,such as the quantum anomalous Hall effect and topological superconductivity discovered in Bi_(2)Te_(3)-based thin films and heterostructures,have shaped research directions in the field of condensed matter physics.In Bi_(2)Te_(3)-based films and heterostructures,delicate control of the carrier transport,film composition,and microstructure are prerequisites for successful device operations as well as for experimental verification of exotic topological phenomena.This review summarizes the recent progress made in atomic defect engineering,carrier tuning,and band engineering down to a nanoscale regime and how it relates to the growth and fabrication of high-quality Bi_(2)Te_(3)-based films.The review also briefly discusses the physical insight into the exciting field of topological phenomena that were so dramatically realized in Bi_(2)Te_(3)-and Bi_(2)Se_(3)‐based structures.It is expected that Bi_(2)Te_(3)-based thin films and heterostructures will play an ever more prominent role as flexible TE devices collecting and converting low-level(body)heat into electricity for numerous electronic applications.It is also likely that such films will continue to be a remarkable platform for the realization of novel topological phenomena.
基金supported by China Ministry of Science and Technology under Contract of 2016YFA(0202801)the National Natural Science Foundation of China(21521091,21390393,U1463202,21471089,21671117,21703219 and 21371023)China Postdoctoral Science Foundation(2017M620738)
文摘The ever-growing market demands for lithium ion batteries have stimulated numerous research efforts aiming at the exploration of novel electrode materials with higher capacity and long-term cycling stability.Two-dimensional (2D)nanomaterials and their heterostructures are an intense area of study and promise great potential in electrochemical lithium storage owing to their unique properties that result from structural planar confinement.Here we report a microwave chemistry strategy to integrate ultrathin SnO2 nanosheets into graphene layer to construct surface-to-surface 2D heterostructured architectures,which can provide unique structural planar confinement for highly reversible electrochemical lithium storage.The as-synthesized 2D SnO2/graphene heterostructures can exhibit high reversible capacity of 688.5mAh g^-1 over 500cycles with excellent long-term cycling stability and good rate capability when used as anode materials for lithium ion batteries.The present work definitely reveals the advantages of 2D heterostructures featured with a surface-to-surface stack between two different nanosheets in energy storage and conversion devices.
基金The project supported by National Natural Science Foundation of China under Grant No. 10347004.
文摘We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron area/density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron＇s, the spin-splitting states of the polaron are more stable than electron＇s.
文摘2D materials including graphene and TMDs have proven interesting physical properties and promising optoelectronic applications.We reviewed the growth,characterization and optoelectronics based on 2D TMDs and their heterostructures,and demonstrated their unique and high quality of performances.For example,we observed the large mobility,fast response and high photo-responsivity in Mo S;,WS;and WSe;phototransistors,as well as the novel performances in vd W heterostructures such as the strong interlayer coupling,am-bipolar and rectifying behaviour,and the obvious photovoltaic effect.It is being possible that 2D family materials could play an increasingly important role in the future nano- and opto-electronics,more even than traditional semiconductors such as silicon.
