Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial applications.Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess ...Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial applications.Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess excellent thermoelectric,electronic,transport,and optical properties.However,the fabrication of large-scale and high-quality monolayer Pd2Se3 is still challenging.Here,we report the synthesis of large-scale and high-quality monolayer Pd2Se3 on graphene-SiC(0001)by a two-step epitaxial growth.The atomic structure of Pd2Se3 was investigated by scanning tunneling microscope(STM)and confirmed by non-contact atomic force microscope(nc-AFM).Two subgroups of Se atoms have been identified by nc-AFM image in agreement with the theoretically predicted atomic structure.Scanning tunneling spectroscopy(STS)reveals a bandgap of 1.2 eV,suggesting that monolayer Pd2Se3 can be a candidate for photoelectronic applications.The atomic structure and defect levels of a single Se vacancy were also investigated.The spatial distribution of STS near the Se vacancy reveals a highly anisotropic electronic behavior.The two-step epitaxial synthesis and characterization of Pd2Se3 provide a promising platform for future investigations and applications.展开更多
In this paper, we are going to study the surface structure and existing symmetry by simulation of a quasicrystal Al-Pd- Mn. Quasicrystals have unique properties in their own structure. In the surface structure general...In this paper, we are going to study the surface structure and existing symmetry by simulation of a quasicrystal Al-Pd- Mn. Quasicrystals have unique properties in their own structure. In the surface structure generally we should pay attention to two subjects. Firstly, what kind of atoms have situated on the surface and secondly the form of collecting atoms by each other sides. Usually, there are different ways for answer to these questions. In this study, Low Energy Ion Scattering (LEIS) technique has been applied. We select a representative cell by using gained information from Low Energy Electron Diffraction (LEED) technique, and give the information to the SABRE computer program. This computer program has been run for azimuthally angles 0 - 180 degrees in the intervals of 9 degree and its output has been analyzed for gaining azimuthally scan. The azimuthally scan shows the existing of a symmetry 72 degree on the surface of this quasicrystal.展开更多
目的研究3种带锈青铜及裸青铜文物材料在3种环境模拟液中的腐蚀发展行为。方法采用动电位扫描和SEM-EDS等方法研究试样的腐蚀特征和现象。结果在模拟大气环境介质中,电位在50~160 m V阳极极化范围内,与其他三种青铜材料相比,带CuCl锈青...目的研究3种带锈青铜及裸青铜文物材料在3种环境模拟液中的腐蚀发展行为。方法采用动电位扫描和SEM-EDS等方法研究试样的腐蚀特征和现象。结果在模拟大气环境介质中,电位在50~160 m V阳极极化范围内,与其他三种青铜材料相比,带CuCl锈青铜的阳极腐蚀电流密度最小;在模拟海水介质中,锈蚀青铜的腐蚀电流密度略大于裸青铜的;在模拟SO_2环境介质中,4种青铜试样的Rp值均大于大气环境介质中的。结论在模拟大气环境介质中,且阳极极化电位接近自腐蚀电位时,CuCl锈对青铜基体具有一定的保护性;在模拟海水环境介质中,带锈青铜的表面锈对基体没有保护作用;在模拟SO_2环境介质中,与在模拟大气环境介质中相比,SO_3^(2-)的引入会抑制青铜的腐蚀。表面形貌和能谱分析结果表明,裸青铜、CuCl锈青铜和混合锈青铜在模拟SO_2环境介质中,有点蚀现象发生,对粉状锈的生成有抑制作用。展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0202300,2018YFA0305800,and 2019YFA0308500)the National Natural Science Foundation of China(Grant Nos.51922011,51872284,and 61888102)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB28000000)the Science Fund from University of the Chinese Academy of Sciences.
文摘Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial applications.Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess excellent thermoelectric,electronic,transport,and optical properties.However,the fabrication of large-scale and high-quality monolayer Pd2Se3 is still challenging.Here,we report the synthesis of large-scale and high-quality monolayer Pd2Se3 on graphene-SiC(0001)by a two-step epitaxial growth.The atomic structure of Pd2Se3 was investigated by scanning tunneling microscope(STM)and confirmed by non-contact atomic force microscope(nc-AFM).Two subgroups of Se atoms have been identified by nc-AFM image in agreement with the theoretically predicted atomic structure.Scanning tunneling spectroscopy(STS)reveals a bandgap of 1.2 eV,suggesting that monolayer Pd2Se3 can be a candidate for photoelectronic applications.The atomic structure and defect levels of a single Se vacancy were also investigated.The spatial distribution of STS near the Se vacancy reveals a highly anisotropic electronic behavior.The two-step epitaxial synthesis and characterization of Pd2Se3 provide a promising platform for future investigations and applications.
文摘In this paper, we are going to study the surface structure and existing symmetry by simulation of a quasicrystal Al-Pd- Mn. Quasicrystals have unique properties in their own structure. In the surface structure generally we should pay attention to two subjects. Firstly, what kind of atoms have situated on the surface and secondly the form of collecting atoms by each other sides. Usually, there are different ways for answer to these questions. In this study, Low Energy Ion Scattering (LEIS) technique has been applied. We select a representative cell by using gained information from Low Energy Electron Diffraction (LEED) technique, and give the information to the SABRE computer program. This computer program has been run for azimuthally angles 0 - 180 degrees in the intervals of 9 degree and its output has been analyzed for gaining azimuthally scan. The azimuthally scan shows the existing of a symmetry 72 degree on the surface of this quasicrystal.
文摘目的研究3种带锈青铜及裸青铜文物材料在3种环境模拟液中的腐蚀发展行为。方法采用动电位扫描和SEM-EDS等方法研究试样的腐蚀特征和现象。结果在模拟大气环境介质中,电位在50~160 m V阳极极化范围内,与其他三种青铜材料相比,带CuCl锈青铜的阳极腐蚀电流密度最小;在模拟海水介质中,锈蚀青铜的腐蚀电流密度略大于裸青铜的;在模拟SO_2环境介质中,4种青铜试样的Rp值均大于大气环境介质中的。结论在模拟大气环境介质中,且阳极极化电位接近自腐蚀电位时,CuCl锈对青铜基体具有一定的保护性;在模拟海水环境介质中,带锈青铜的表面锈对基体没有保护作用;在模拟SO_2环境介质中,与在模拟大气环境介质中相比,SO_3^(2-)的引入会抑制青铜的腐蚀。表面形貌和能谱分析结果表明,裸青铜、CuCl锈青铜和混合锈青铜在模拟SO_2环境介质中,有点蚀现象发生,对粉状锈的生成有抑制作用。
