Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely...Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely used in electronic and optoelectronic applications, two critical issues need to be addressed, which are thickness-controllable fabrication and doping modulation of TMDCs. In this work, we successfully obtained monolayer WS2 and achieved its efficient doping by chemical vapor deposition and chemical doping, respectively. The n-and p-type dopings of the monolayer WS2 were achieved by drop coating electron donor and acceptor solutions of triphenylphosphine(PPh3) and gold chloride(AuCl_3), respectively, on the surface, which donates and captures electrons to/from the WS2 surface through charge transfer, respectively. Both doping effects were investigated in terms of the electrical properties of the fabricated field effect transistors. After chemical doping, the calculated mobility and density of electrons/holes are around 74.6/39.5 cm^2 · V^(-1) ·s^(-1)and 1.0 x 10^(12)/4.2 x 10^(11) cm^(-2), respectively. Moreover, we fabricated a lateral WS2 p-n homojunction consisting of nondoped n-type and p-doped p-type regions, which showed great potential for photodetection with a response time of 1.5 s and responsivity of 5.8 A/W at V_G = 0 V and V_D = 1 V under 532 nm light illumination.展开更多
Two‐dimensional(2D)materials show outstanding properties such as dangling bond‐free surfaces,strong in‐plane while weak out‐of‐plane bonding,layer‐dependent electronic structures,and tunable electronic and optoe...Two‐dimensional(2D)materials show outstanding properties such as dangling bond‐free surfaces,strong in‐plane while weak out‐of‐plane bonding,layer‐dependent electronic structures,and tunable electronic and optoelectronic properties,making them promising for numerous applications.Integrating 2D inorganics with organic materials to make van der Waals heterostructures at the 2D thickness limit has created new platforms for fabricating on‐demand multifunctional devices.To further broaden the limited choices of 2D inorganic‐based heterostructures,a wide range of available 2D organic materials with tunable properties have opened new opportunities for designing large numbers of heterostructures with 2D inorganic materials.This review aims to attract the attention of researchers toward this emerging 2D organic−inorganic field.We first highlight recent progress in organic−inorganic heterostructures and their synthesis and then discuss their potential applications,such as field‐effect transistors,photodetectors,solar cells,and neuromorphic computing devices.In the end,we present a summary of challenges and opportunities in this field.展开更多
Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D...Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors.Here,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces dramatically.The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within seconds.This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.展开更多
Two-dimensional(2D)materials offer novel platforms to meet the increasing demands of next-generation miniaturized electronics.Among them,the recently emerged 2D Bi_(2)O_(2)Se with unique non-van der Waals interlayer ...Two-dimensional(2D)materials offer novel platforms to meet the increasing demands of next-generation miniaturized electronics.Among them,the recently emerged 2D Bi_(2)O_(2)Se with unique non-van der Waals interlayer interaction,high mobility,sizeable bandgap,and capability to fabricate homologous heterojunction,is of particular interest.In this Review,we introduce recent progress in preparation,transfer,mechanical and electrical properties,and electronic applications of 2D Bi_(2)O_(2)Se.First,we summarize methodologies to synthesize and massively produce 2D Bi_(2)O_(2)Se,as well as recent advances in transferring them from growth substrate to arbitrary substrates.Then,we review current understandings on the intrinsic mechanical properties of Bi_(2)O_(2)Se at 2D thickness limit,and its in-plane and out-of-plane electrical properties.Electronic devices including field-effect transistors,memristors,and sensors based on 2D Bi_(2)O_(2)Se for neuromorphic computing,memory,logic,and integrated circuits are discussed.Finally,challenges and prospects for the development of 2D Bi_(2)O_(2)Se are proposed.展开更多
The non-Markov process exists widely in thermodymanic process,while it usually requires the packing of many transistors and memories with great system complexity in a traditional device structure to minic such functio...The non-Markov process exists widely in thermodymanic process,while it usually requires the packing of many transistors and memories with great system complexity in a traditional device structure to minic such functions.Two-dimensional(2D)material-based resistive random access memory(RRAM)devices have the potential for next-generation computing systems with much-reduced complexity.Here,we achieve a non-Markov chain in an individual RRAM device based on 2D mineral material mica with a vertical metal/mica/metal structure.We find that the potassium ions(K+)in 2D mica gradually move in the direction of the applied electric field,making the initially insulating mica conductive.The accumulation of K+is changed by an electric field,and the 2D-mica RRAM has both single and double memory windows,a high on/off ratio,decent stability,and repeatability.This is the first time a non-Markov chain process has been established in a single RRAM,in which the movement of K+is dependent on the stimulated voltage as well as their past states.This work not only uncovers an intrinsic inner ionic conductivity of 2D mica,but also opens the door for the production of such RRAM devices with numerous functions and applications.展开更多
Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surfa...Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding.However,the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit.Here,we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source.Taking hexagonal Fe_(1-x)S as an example,the thickness of the Fe_(1-x)S flakes is down to 3 nm with a lateral size of over 100 μm.Importantly,we find ordered cation Fe vacancies in Fe_(1-x)S,which is distinct from layered TMCs like MoS_(2) where anion vacancies are commonly observed.Low-temperature transport measurements and theoretical calculations show that 2D Fe_(1-x)S is a stable semiconductor with a narrow bandgap of60 meV.In addition to Fe_(1-x)S,the method is universal in growing various non-layered 2D TMCs containing ordered cation vacancies,including Fe_(1-x)Se,Co_(1-x)S,Cr_(1-x)S,and V_(1-x)S.This work paves the way to grow and exploit properties of non-layered materials at 2D thickness limit.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.21405109)Seed Foundation of State Key Laboratory of Precision Measurement Technology and Instruments,China(Grant No.1710)
文摘Transition metal dichalcogenides(TMDCs) belong to a subgroup of two-dimensional(2 D) materials which usually possess thickness-dependent band structures and semiconducting properties. Therefore, for TMDCs to be widely used in electronic and optoelectronic applications, two critical issues need to be addressed, which are thickness-controllable fabrication and doping modulation of TMDCs. In this work, we successfully obtained monolayer WS2 and achieved its efficient doping by chemical vapor deposition and chemical doping, respectively. The n-and p-type dopings of the monolayer WS2 were achieved by drop coating electron donor and acceptor solutions of triphenylphosphine(PPh3) and gold chloride(AuCl_3), respectively, on the surface, which donates and captures electrons to/from the WS2 surface through charge transfer, respectively. Both doping effects were investigated in terms of the electrical properties of the fabricated field effect transistors. After chemical doping, the calculated mobility and density of electrons/holes are around 74.6/39.5 cm^2 · V^(-1) ·s^(-1)and 1.0 x 10^(12)/4.2 x 10^(11) cm^(-2), respectively. Moreover, we fabricated a lateral WS2 p-n homojunction consisting of nondoped n-type and p-doped p-type regions, which showed great potential for photodetection with a response time of 1.5 s and responsivity of 5.8 A/W at V_G = 0 V and V_D = 1 V under 532 nm light illumination.
基金supported by the National Science Fund for Distinguished Young Scholars(No.52125309)the National Natural Science Foundation of China(Nos.51991343,52188101,and 51991340)+2 种基金the National Key R&D Program(No.2018YFA0307300)Guangdong Innovative and Entrepreneurial Research Team Program(No.2017ZT07C341)the Shenzhen Basic Research Project(No.JCYJ20200109144616617).
文摘Two‐dimensional(2D)materials show outstanding properties such as dangling bond‐free surfaces,strong in‐plane while weak out‐of‐plane bonding,layer‐dependent electronic structures,and tunable electronic and optoelectronic properties,making them promising for numerous applications.Integrating 2D inorganics with organic materials to make van der Waals heterostructures at the 2D thickness limit has created new platforms for fabricating on‐demand multifunctional devices.To further broaden the limited choices of 2D inorganic‐based heterostructures,a wide range of available 2D organic materials with tunable properties have opened new opportunities for designing large numbers of heterostructures with 2D inorganic materials.This review aims to attract the attention of researchers toward this emerging 2D organic−inorganic field.We first highlight recent progress in organic−inorganic heterostructures and their synthesis and then discuss their potential applications,such as field‐effect transistors,photodetectors,solar cells,and neuromorphic computing devices.In the end,we present a summary of challenges and opportunities in this field.
基金This work was supported by the National Key R&D Program(2018YFA0307300)the National Natural Science Foundation of China(51991343,51991340,52188101 and 51920105002)+3 种基金the China Postdoctoral Science Foundation(2021M701948)the National Science Fund for Distinguished Young Scholars(52125309)Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20220818101014029).
文摘Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality materials.However,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial semiconductors.Here,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces dramatically.The sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within seconds.This work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.
基金We acknowledge support from the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110980)the National Natural Science Foundation of China(Nos.51991343,51991340,52188101,and 52102179)+3 种基金the National Science Fund for Distinguished Young Scholars(No.52125309)Guangdong Innovative and Entrepreneurial Research Team Program(No.2017ZT07C341)the Bureau of Industry and Information Technology of Shenzhen for the“2017 Graphene Manufacturing Innovation Center Project”(No.201901171523)the Shenzhen Basic Research Program(No.JCYJ20200109144616617)。
文摘Two-dimensional(2D)materials offer novel platforms to meet the increasing demands of next-generation miniaturized electronics.Among them,the recently emerged 2D Bi_(2)O_(2)Se with unique non-van der Waals interlayer interaction,high mobility,sizeable bandgap,and capability to fabricate homologous heterojunction,is of particular interest.In this Review,we introduce recent progress in preparation,transfer,mechanical and electrical properties,and electronic applications of 2D Bi_(2)O_(2)Se.First,we summarize methodologies to synthesize and massively produce 2D Bi_(2)O_(2)Se,as well as recent advances in transferring them from growth substrate to arbitrary substrates.Then,we review current understandings on the intrinsic mechanical properties of Bi_(2)O_(2)Se at 2D thickness limit,and its in-plane and out-of-plane electrical properties.Electronic devices including field-effect transistors,memristors,and sensors based on 2D Bi_(2)O_(2)Se for neuromorphic computing,memory,logic,and integrated circuits are discussed.Finally,challenges and prospects for the development of 2D Bi_(2)O_(2)Se are proposed.
基金This work was supported by the National Natural Science Foundation of China(51920105002,51991340,51722206,and 51991343)Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341)+1 种基金the Bureau of Industry and Information Technology of Shenzhen for the“2017 Graphene Manufacturing Innovation Center Project”(201901171523)the Shenzhen Basic Research Program(JCYJ20200109144620815 and JCYJ20200109144616617).
文摘The non-Markov process exists widely in thermodymanic process,while it usually requires the packing of many transistors and memories with great system complexity in a traditional device structure to minic such functions.Two-dimensional(2D)material-based resistive random access memory(RRAM)devices have the potential for next-generation computing systems with much-reduced complexity.Here,we achieve a non-Markov chain in an individual RRAM device based on 2D mineral material mica with a vertical metal/mica/metal structure.We find that the potassium ions(K+)in 2D mica gradually move in the direction of the applied electric field,making the initially insulating mica conductive.The accumulation of K+is changed by an electric field,and the 2D-mica RRAM has both single and double memory windows,a high on/off ratio,decent stability,and repeatability.This is the first time a non-Markov chain process has been established in a single RRAM,in which the movement of K+is dependent on the stimulated voltage as well as their past states.This work not only uncovers an intrinsic inner ionic conductivity of 2D mica,but also opens the door for the production of such RRAM devices with numerous functions and applications.
基金supported by the National Science Fund for Distinguished Young Scholars(52125309)the National Natural Science Foundation of China(51991343,51920105002,51991340,52188101,and 11974156)+3 种基金Guangdong Innovative and Entrepreneurial Research Team Program(2017ZT07C341 and 2019ZT08C044)the Bureau of Industry and Information Technology of Shenzhen for the “2017 Graphene Manufacturing Innovation Center Project”(201901171523)Shenzhen Basic Research Project(JCYJ20200109144616617 and JCYJ20190809180605522)Shenzhen Science and Technology Program(KQTD20190929173815000 and 20200925161102001)。
文摘Two-dimensional(2D)transition metal chalcogenides(TMCs)are promising for nanoelectronics and energy applications.Among them,the emerging non-layered TMCs are unique due to their unsaturated dangling bonds on the surface and strong intralayer and interlayer bonding.However,the synthesis of non-layered 2D TMCs is challenging and this has made it difficult to study their structures and properties at thin thickness limit.Here,we develop a universal dual-metal precursors method to grow non-layered TMCs in which a mixture of a metal and its chloride serves as the metal source.Taking hexagonal Fe_(1-x)S as an example,the thickness of the Fe_(1-x)S flakes is down to 3 nm with a lateral size of over 100 μm.Importantly,we find ordered cation Fe vacancies in Fe_(1-x)S,which is distinct from layered TMCs like MoS_(2) where anion vacancies are commonly observed.Low-temperature transport measurements and theoretical calculations show that 2D Fe_(1-x)S is a stable semiconductor with a narrow bandgap of60 meV.In addition to Fe_(1-x)S,the method is universal in growing various non-layered 2D TMCs containing ordered cation vacancies,including Fe_(1-x)Se,Co_(1-x)S,Cr_(1-x)S,and V_(1-x)S.This work paves the way to grow and exploit properties of non-layered materials at 2D thickness limit.
