Silicene, a two-dimensional(2D) honeycomb structure similar to graphene, has been successfully fabricated on various substrates. This work will mainly review the syntheses and the corresponding prope√rties o√f silic...Silicene, a two-dimensional(2D) honeycomb structure similar to graphene, has been successfully fabricated on various substrates. This work will mainly review the syntheses and the corresponding prope√rties o√f silicene and√ silice√ne–graphene layered structures on Ir(111) substrates. For silicene on Ir(111), the buckled(3 ×3) silicene/(7 ×7)Ir(111) configuration and its electronic structure are fully discussed. For silicene–graphene layered structures, silicene layer can be constructed underneath graphene layer by an intercalation method. These results indicate the possibility of integrating silicene with graphene and may link up with potential applications in nanoelectronics and related areas.展开更多
Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/Si C(0001) by molecular beam epitaxy, which are investigated by scanning ...Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/Si C(0001) by molecular beam epitaxy, which are investigated by scanning tunneling microscopy. The two types of islands distinguished by flat or round tops are revealed, indicating bimodal growth of Fe. The atomic structures on the top surfaces of flat islands are also clearly resolved. Our results may improve the understanding of the mechanisms of metals deposited on graphene and pave the way for future spintronic applications of Fe/graphene systems.展开更多
We perform molecular beam epitaxy growth and scanning tunneling microscopy study of copper diselenide (CuSe2 ) films on SrTiO3 (001). Using a Se-rich condition, the single-phase pyrite CuSe2 grows in the Stranski-...We perform molecular beam epitaxy growth and scanning tunneling microscopy study of copper diselenide (CuSe2 ) films on SrTiO3 (001). Using a Se-rich condition, the single-phase pyrite CuSe2 grows in the Stranski-Krastanov (layer-plus-island) mode with a preferential orientation of (111). Our careful inspection of both the as-grown and post-annealed CuSe2 films at various temperatures invariably shows a Cu-terminated surface, which, depending on the annealing temperature, reconstructs into two distinct structures 2 ×√3 and √x ×√3-R30°. The Cu termi- nation is supported by the depressed density of states near the Fermi level, measured by in-situ low temperature scanning tunneling spectroscopy. Our study helps understand the preparation and surface chemistry of transition metal pyrite dichalcogenides thin films.展开更多
Intercalation of atomic species is a practicable method for epitaxial graphene to adjust the electronic band structure and to tune the coupling between graphene and Si C substrate. In this work, atomically flat epitax...Intercalation of atomic species is a practicable method for epitaxial graphene to adjust the electronic band structure and to tune the coupling between graphene and Si C substrate. In this work, atomically flat epitaxial graphene is prepared on 4H-SiC(0001) using the flash heating method in an ultrahigh vacuum system. Scanning tunneling microscopy, Raman spectroscopy and electrical transport measurements are utilized to investigate surface morphological structures and transport properties of pristine and Er-intercalated epitaxial graphene. It is found that Er atoms are intercalated underneath the graphene layer after annealing at 900℃, and the intercalation sites of Er atoms are located mainly at the bufferlayer/monolayer-graphene interface in monolayer domains. We also report the different behaviors of Er intercalation in monolayer and bilayer regions, and the experimental results show that the diffusion barrier for Er intercalated atoms in the buffer-layer/monolayer interface is at least 0.2 eV higher than that in the first/second graphene-layer interface. The appearance of Er atoms is found to have distinct impacts on the electronic transports of epitaxial graphene on SiC(0001).展开更多
Van der Waals stacking of two-dimensional crystals with rotation or mismatch in lattice constants gives rise to rich physical phenomena that are closely related to the strong correlations and band topology.Twisted gra...Van der Waals stacking of two-dimensional crystals with rotation or mismatch in lattice constants gives rise to rich physical phenomena that are closely related to the strong correlations and band topology.Twisted graphene and silicene heterobilayers have been theoretically predicted to host a tunable transport gap due to the mismatch of Dirac cones in the graphene and silicene layers.However,experimental realization of such twisted structure is challenging.Here,we report the formation of twisted graphene/silicene bilayers on Ru(0001)crystal via intercalation.Different moirépatterns form as single-crystalline graphene grows over different grains of the Ru surface.After silicon intercalation,graphene/silicene bilayers are observed with different twisting angles on top of different grains of the Ru substrate.Our work provides a new pathway towards construction of graphene based twisted heterobilayers.展开更多
Microscopic features of graphene segregated on Ni films prior to chemical transfer--including atomic structures of monolayers and bilayers, Moire patterns due to non-AB stacking, as well as wrinkles and ripples caused...Microscopic features of graphene segregated on Ni films prior to chemical transfer--including atomic structures of monolayers and bilayers, Moire patterns due to non-AB stacking, as well as wrinkles and ripples caused by strain effects-have been characterized in detail by high-resolution scanning tunneling microscopy (STM). We found that the stacking geometry of the bilayer graphene usually deviates from the traditional Bernal stacking (or so-called AB stacking), resulting in the formation of a variety of Moir6 patterns. The relative rotations inside the bilayer were then qualitatively deduced from the relationship between Moir6 patterns and carbon lattices. Moreover, we found that typical defects such as wrinkles and ripples tend to evolve around multi-step boundaries of Ni, thus reflecting strong perturbations from substrate corrugations. These investigations of the morphology and the mechanism of formation of wrinkles and ripples are fundamental topics in graphene research. This work is expected to contribute to the exploration of electronic and transport properties of wrinkles and ripples.展开更多
A comprehensive picture of the initial stages of silicene growth on graphite is drawn.Evidence is shown that quasiparticle interferences play a crucial role in the formation of the observed silicene configurations.We ...A comprehensive picture of the initial stages of silicene growth on graphite is drawn.Evidence is shown that quasiparticle interferences play a crucial role in the formation of the observed silicene configurations.We propose,on one hand,that the charge modulations caused by those quantum interferences serve as templates and guide the incoming Si atoms to self-assemble to the unique(√3 x√3)R30°honeycomb atomic arrangement.On the other hand,their limited extension limits the growth to about 150 Si atoms under our present deposition conditions.The here proposed electrostatic interaction finally explains the unexpected stability of the observed silicene islands over time and with temperature.Despite the robust guiding nature of those quantum interferences during the early growth phase,we demonstrate that the window of experimental conditions for silicene growth is quite narrow,making it an extremely challenging experimental task.Finally,it is shown that the experimentally observed threedimensional silicon clusters might very well be the simple result of the end of the silicene growth resulting from the limited extent of the quasi-particle interferences.展开更多
The epitaxial growth of Ge on Si(111) covered with the 0.3 nm thick SiO2 film is studied by scanning tunneling microscopy. Nanoareas of bare Si in the SiO2 film are prepared by Ge deposition at a temperature in the ra...The epitaxial growth of Ge on Si(111) covered with the 0.3 nm thick SiO2 film is studied by scanning tunneling microscopy. Nanoareas of bare Si in the SiO2 film are prepared by Ge deposition at a temperature in the range of 570℃-650℃ due to the formation of volatile SiO and GeO molecules. The surface morphology of Ge layers grown further at 360℃-500℃ is composed of facets and large flat areas with the Ge(111)-c(2 × 8) reconstruction which is typical of unstrained Ge. Orientations of the facets, which depend on the growth temperature, are identified. The growth at 250℃-300℃ produces continuous epitaxial Ge layers on Si(111). A comparison of the surface morphology of Ge layers grown on bare and SiO2-film covered Si(111) surfaces shows a significantly lower Ge-Si intermixing in the latter case due to a reduction in the lattice strain. The found approach to reduce the strain suggests the opportunity of the thin continuous epitaxial Ge layer formation on Si(111).展开更多
Surface morphological features and nanostructures generated during SiC graphitization process can significantly affect fabrication of high-quality epitaxial graphene on semiconductor substrates.In this work,we investi...Surface morphological features and nanostructures generated during SiC graphitization process can significantly affect fabrication of high-quality epitaxial graphene on semiconductor substrates.In this work,we investigate the surface morphologies and atomic structures during graphitization process of 4H-SiC(0001) using scanning tunneling microscopy.Our high-magnified scanning-tunneling-microscope images exhibit the appearance and gradual developments of SiC(1 × 1)nanostructures after 1100℃ cleaning treatments,irregularly distributed among carbon nanocaps and(√3×√3) reconstruction domains.A model for the formation and growth progression of SiC(1 × 1) nanostructures has been proposed.When post-annealing temperature reaches 1300 ℃,the nanoholes and nanoislands can be observed on the surface,and multilayer graphene is often detected lying on the top surface of those nanoislands.These results provide profound insights into the complex evolution process of surface morphology during SiC thermal decomposition and will shed light on fabrication of SiC nanostructures and graphene nanoflakes.展开更多
The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been su...The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been successfully fabricated via phase transition engineering.However,the understanding of structural phase transition ofβ-Sn(001)thin films is still elusive.Here,we report the direct growth of ultrathinβ-Sn(001)films epitaxially on the highly oriented pyrolytic graphite(HOPG)substrate and the characterization of intricate structural-transition-induced superstructures.The morphology was obtained by using atomic force microscopy(AFM)and low-temperature scanning tunneling microscopy(STM),indicating a structure-related bilayer-by-bilayer growth mode.The ultrathinβ-Sn film was made of multiple domains with various superstructures.Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains.The formation mechanism of these superstructures was further discussed based on the structural phase transition ofβtoα-Sn at the atomic-scale thickness.Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit,but also paves a way to investigate their structure-sensitive topological properties.展开更多
Transition-metal chalcogenides(TMCs)materials have attracted increasing interest both for fundamental research and industrial applications.Among all these materials,two-dimensional(2D)compounds with honeycomb-like str...Transition-metal chalcogenides(TMCs)materials have attracted increasing interest both for fundamental research and industrial applications.Among all these materials,two-dimensional(2D)compounds with honeycomb-like structure possess exotic electronic structures.Here,we report a systematic study of TMC monolayer AgTe fabricated by direct depositing Te on the surface of Ag(111)and annealing.Few intrinsic defects are observed and studied by scanning tunneling microscopy,indicating that there are two kinds of AgTe domains and they can form gliding twin-boundary.Then,the monolayer AgTe can serve as the template for the following growth of Te film.Meanwhile,some Te atoms are observed in the form of chains on the top of the bottom Te film.Our findings in this work might provide insightful guide for the epitaxial growth of 2D materials for study of novel physical properties and for future quantum devices.展开更多
Recent experimental breakthroughs open up new opportunities for magnetism in few-atomic-layer twodimensional(2 D) materials, which makes fabrication of new magnetic 2 D materials a fascinating issue.Here, we report th...Recent experimental breakthroughs open up new opportunities for magnetism in few-atomic-layer twodimensional(2 D) materials, which makes fabrication of new magnetic 2 D materials a fascinating issue.Here, we report the growth of monolayer VSe_2 by molecular beam epitaxy(MBE) method. Electronic properties measurements by scanning tunneling spectroscopy(STS) method revealed that the asgrown monolayer VSe_2 has magnetic characteristic peaks in its electronic density of states and a lower work-function at its edges. Moreover, air exposure experiments show air-stability of the monolayer VSe_2. This high-quality monolayer VSe_2, a very air-inert 2 D material with magnetism and low edge work function, is promising for applications in developing next-generation low power-consumption, high efficiency spintronic devices and new electrocatalysts.展开更多
基金supported by the National Basic Research Program of China(Grant Nos.2013CBA01600 and 2011CB932700)the National Natural Science Foundation of China(Grant Nos.61222112,61390501,51325204,11334006,and 61306114)+1 种基金the Science Fund from Chinese Academy of Sciences(Grant Nos.1731300500015 and XDB07030100)the Fundamental Research Funds for the Central Universities,China
文摘Silicene, a two-dimensional(2D) honeycomb structure similar to graphene, has been successfully fabricated on various substrates. This work will mainly review the syntheses and the corresponding prope√rties o√f silicene and√ silice√ne–graphene layered structures on Ir(111) substrates. For silicene on Ir(111), the buckled(3 ×3) silicene/(7 ×7)Ir(111) configuration and its electronic structure are fully discussed. For silicene–graphene layered structures, silicene layer can be constructed underneath graphene layer by an intercalation method. These results indicate the possibility of integrating silicene with graphene and may link up with potential applications in nanoelectronics and related areas.
基金the Ministry of Science and Technology of China (Grant Nos. 2019YFA0308600 and 2020YFA0309000)the National Natural Science Foundation of China (Grant Nos. 92365302, 92065201, 22325203, 92265105, 12074247, and 12174252)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB28000000)the Science and Technology Commission of Shanghai Municipality (Grant Nos. 2019SHZDZX01, 19JC1412701 and 20QA1405100) for financial supportfinancial support from the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0302500)。
文摘Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/Si C(0001) by molecular beam epitaxy, which are investigated by scanning tunneling microscopy. The two types of islands distinguished by flat or round tops are revealed, indicating bimodal growth of Fe. The atomic structures on the top surfaces of flat islands are also clearly resolved. Our results may improve the understanding of the mechanisms of metals deposited on graphene and pave the way for future spintronic applications of Fe/graphene systems.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374336 and 61176078
文摘We perform molecular beam epitaxy growth and scanning tunneling microscopy study of copper diselenide (CuSe2 ) films on SrTiO3 (001). Using a Se-rich condition, the single-phase pyrite CuSe2 grows in the Stranski-Krastanov (layer-plus-island) mode with a preferential orientation of (111). Our careful inspection of both the as-grown and post-annealed CuSe2 films at various temperatures invariably shows a Cu-terminated surface, which, depending on the annealing temperature, reconstructs into two distinct structures 2 ×√3 and √x ×√3-R30°. The Cu termi- nation is supported by the depressed density of states near the Fermi level, measured by in-situ low temperature scanning tunneling spectroscopy. Our study helps understand the preparation and surface chemistry of transition metal pyrite dichalcogenides thin films.
基金Project supported by the Natural Science Foundation of Shanghai Science and Technology Committee (Grant No. 18ZR1403300)。
文摘Intercalation of atomic species is a practicable method for epitaxial graphene to adjust the electronic band structure and to tune the coupling between graphene and Si C substrate. In this work, atomically flat epitaxial graphene is prepared on 4H-SiC(0001) using the flash heating method in an ultrahigh vacuum system. Scanning tunneling microscopy, Raman spectroscopy and electrical transport measurements are utilized to investigate surface morphological structures and transport properties of pristine and Er-intercalated epitaxial graphene. It is found that Er atoms are intercalated underneath the graphene layer after annealing at 900℃, and the intercalation sites of Er atoms are located mainly at the bufferlayer/monolayer-graphene interface in monolayer domains. We also report the different behaviors of Er intercalation in monolayer and bilayer regions, and the experimental results show that the diffusion barrier for Er intercalated atoms in the buffer-layer/monolayer interface is at least 0.2 eV higher than that in the first/second graphene-layer interface. The appearance of Er atoms is found to have distinct impacts on the electronic transports of epitaxial graphene on SiC(0001).
基金the Ministry of Science and Technology of China(Nos.2019YFA0308500 and 2018YFA0305800)the National Natural Science Foundation of China(Nos.61888102,51991340,and 52072401)the Chinese Academy of Sciences Project for Young Scientists in Basic Research(No.YSBR-003).
文摘Van der Waals stacking of two-dimensional crystals with rotation or mismatch in lattice constants gives rise to rich physical phenomena that are closely related to the strong correlations and band topology.Twisted graphene and silicene heterobilayers have been theoretically predicted to host a tunable transport gap due to the mismatch of Dirac cones in the graphene and silicene layers.However,experimental realization of such twisted structure is challenging.Here,we report the formation of twisted graphene/silicene bilayers on Ru(0001)crystal via intercalation.Different moirépatterns form as single-crystalline graphene grows over different grains of the Ru surface.After silicon intercalation,graphene/silicene bilayers are observed with different twisting angles on top of different grains of the Ru substrate.Our work provides a new pathway towards construction of graphene based twisted heterobilayers.
基金Acknowledgements This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 20973013, 51072004, 50821061, 20833001, 21073003, 20973006, and 50802003) and the Ministry of Science and Technology of China (Grant Nos. 2007CB936203, 2011CB921903, and 2009CB929403). Ruiqi Zhao also thanks the Doctoral Foundation of Henan Polytechnic University (Grant No. B2009-90).
文摘Microscopic features of graphene segregated on Ni films prior to chemical transfer--including atomic structures of monolayers and bilayers, Moire patterns due to non-AB stacking, as well as wrinkles and ripples caused by strain effects-have been characterized in detail by high-resolution scanning tunneling microscopy (STM). We found that the stacking geometry of the bilayer graphene usually deviates from the traditional Bernal stacking (or so-called AB stacking), resulting in the formation of a variety of Moir6 patterns. The relative rotations inside the bilayer were then qualitatively deduced from the relationship between Moir6 patterns and carbon lattices. Moreover, we found that typical defects such as wrinkles and ripples tend to evolve around multi-step boundaries of Ni, thus reflecting strong perturbations from substrate corrugations. These investigations of the morphology and the mechanism of formation of wrinkles and ripples are fundamental topics in graphene research. This work is expected to contribute to the exploration of electronic and transport properties of wrinkles and ripples.
文摘A comprehensive picture of the initial stages of silicene growth on graphite is drawn.Evidence is shown that quasiparticle interferences play a crucial role in the formation of the observed silicene configurations.We propose,on one hand,that the charge modulations caused by those quantum interferences serve as templates and guide the incoming Si atoms to self-assemble to the unique(√3 x√3)R30°honeycomb atomic arrangement.On the other hand,their limited extension limits the growth to about 150 Si atoms under our present deposition conditions.The here proposed electrostatic interaction finally explains the unexpected stability of the observed silicene islands over time and with temperature.Despite the robust guiding nature of those quantum interferences during the early growth phase,we demonstrate that the window of experimental conditions for silicene growth is quite narrow,making it an extremely challenging experimental task.Finally,it is shown that the experimentally observed threedimensional silicon clusters might very well be the simple result of the end of the silicene growth resulting from the limited extent of the quasi-particle interferences.
文摘The epitaxial growth of Ge on Si(111) covered with the 0.3 nm thick SiO2 film is studied by scanning tunneling microscopy. Nanoareas of bare Si in the SiO2 film are prepared by Ge deposition at a temperature in the range of 570℃-650℃ due to the formation of volatile SiO and GeO molecules. The surface morphology of Ge layers grown further at 360℃-500℃ is composed of facets and large flat areas with the Ge(111)-c(2 × 8) reconstruction which is typical of unstrained Ge. Orientations of the facets, which depend on the growth temperature, are identified. The growth at 250℃-300℃ produces continuous epitaxial Ge layers on Si(111). A comparison of the surface morphology of Ge layers grown on bare and SiO2-film covered Si(111) surfaces shows a significantly lower Ge-Si intermixing in the latter case due to a reduction in the lattice strain. The found approach to reduce the strain suggests the opportunity of the thin continuous epitaxial Ge layer formation on Si(111).
基金Project supported by the Natural Science Foundation of Shanghai Science and Technology Committee (Grant No. 18ZR1403300)。
文摘Surface morphological features and nanostructures generated during SiC graphitization process can significantly affect fabrication of high-quality epitaxial graphene on semiconductor substrates.In this work,we investigate the surface morphologies and atomic structures during graphitization process of 4H-SiC(0001) using scanning tunneling microscopy.Our high-magnified scanning-tunneling-microscope images exhibit the appearance and gradual developments of SiC(1 × 1)nanostructures after 1100℃ cleaning treatments,irregularly distributed among carbon nanocaps and(√3×√3) reconstruction domains.A model for the formation and growth progression of SiC(1 × 1) nanostructures has been proposed.When post-annealing temperature reaches 1300 ℃,the nanoholes and nanoislands can be observed on the surface,and multilayer graphene is often detected lying on the top surface of those nanoislands.These results provide profound insights into the complex evolution process of surface morphology during SiC thermal decomposition and will shed light on fabrication of SiC nanostructures and graphene nanoflakes.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61674045,61911540074,and 21622304)the Fund from the Ministry of Science and Technology of China(Grant No.2016YFA0200700)+1 种基金the Strategic Priority Research Program and Key Research Program of Frontier Sciences(Chinese Academy of Sciences)(Grant Nos.XDB30000000 and QYZDB-SSW-SYS031)Zhihai Cheng was supported by the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China(Grant No.21XNLG27).
文摘The ultrathinβ-Sn(001)films have attracted tremendous attention owing to its topological superconductivity(TSC),which hosts Majorana bound state(MBSs)for quantum computation.Recently,β-Sn(001)thin films have been successfully fabricated via phase transition engineering.However,the understanding of structural phase transition ofβ-Sn(001)thin films is still elusive.Here,we report the direct growth of ultrathinβ-Sn(001)films epitaxially on the highly oriented pyrolytic graphite(HOPG)substrate and the characterization of intricate structural-transition-induced superstructures.The morphology was obtained by using atomic force microscopy(AFM)and low-temperature scanning tunneling microscopy(STM),indicating a structure-related bilayer-by-bilayer growth mode.The ultrathinβ-Sn film was made of multiple domains with various superstructures.Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains.The formation mechanism of these superstructures was further discussed based on the structural phase transition ofβtoα-Sn at the atomic-scale thickness.Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit,but also paves a way to investigate their structure-sensitive topological properties.
基金This project was supported by the Ministry of Science and Technology(MOST)of China(No.2016YFA0200700)the National Natural Science Foundation of China(NSFC)(Nos.61674045 and 61911540074)+2 种基金the Strategic Priority Research Program and Key Research Program of Frontier Sciences(Chinese Academy of Sciences,CAS)(Nos.XDB30000000 and QYZDB-SSW-SYS031)Grant-in-Aid for Scientific Research from Japan Society for the Promotion of Science(JSPS)from the Ministry of Education,Culture,Sports,Science,and Technology of Japan(Nos.JP16H06327,JP16H06504,JP17H01061,and JP17H010610)Osaka University’s International Joint Research Promotion Program(Nos.J171013014,J171013007,J181013006,and Ja19990011).Z.H.C.was supported by the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China(No.21XNLG27).
文摘Transition-metal chalcogenides(TMCs)materials have attracted increasing interest both for fundamental research and industrial applications.Among all these materials,two-dimensional(2D)compounds with honeycomb-like structure possess exotic electronic structures.Here,we report a systematic study of TMC monolayer AgTe fabricated by direct depositing Te on the surface of Ag(111)and annealing.Few intrinsic defects are observed and studied by scanning tunneling microscopy,indicating that there are two kinds of AgTe domains and they can form gliding twin-boundary.Then,the monolayer AgTe can serve as the template for the following growth of Te film.Meanwhile,some Te atoms are observed in the form of chains on the top of the bottom Te film.Our findings in this work might provide insightful guide for the epitaxial growth of 2D materials for study of novel physical properties and for future quantum devices.
基金supported by the National Natural Science Foundation of China(61725107,51572290 and 11334006)National Key Research&Development Projects of China(2016YFA0202301)+1 种基金National Basic Research Program of China(2013CBA01601)Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDPB06)
文摘Recent experimental breakthroughs open up new opportunities for magnetism in few-atomic-layer twodimensional(2 D) materials, which makes fabrication of new magnetic 2 D materials a fascinating issue.Here, we report the growth of monolayer VSe_2 by molecular beam epitaxy(MBE) method. Electronic properties measurements by scanning tunneling spectroscopy(STS) method revealed that the asgrown monolayer VSe_2 has magnetic characteristic peaks in its electronic density of states and a lower work-function at its edges. Moreover, air exposure experiments show air-stability of the monolayer VSe_2. This high-quality monolayer VSe_2, a very air-inert 2 D material with magnetism and low edge work function, is promising for applications in developing next-generation low power-consumption, high efficiency spintronic devices and new electrocatalysts.