Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement o...Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular.展开更多
Hexagonal boron nitride （h-BN） is often prepared by epitaxial growth on metals, and stability of the formed BN/metal interfaces in gaseous environment is a key issue for physicochemical properties of the BN overlaye...Hexagonal boron nitride （h-BN） is often prepared by epitaxial growth on metals, and stability of the formed BN/metal interfaces in gaseous environment is a key issue for physicochemical properties of the BN overlayers. As an illustration here, the structural change of a BN/Ru（0001） interface upon exposure to 02 has been investigated using in situ photoemission electron microscopy （PEEM） and ambient pressure X-ray photoelectron spectroscopy （AP-XPS）. We demonstrate the occurrence of oxygen intercalation of the BN overlayers in 02 atmosphere, which decouples the BN overlayer from the substrate. Comparative studies of oxygen intercalation at BN/Ru（0001） and graphene/Ru（0001） surfaces indicate that the oxygen intercalation of BN overlayers happens more easily than graphene. This finding will be of importance for future applications of BN-based devices and materials under ambient conditions.展开更多
1科学背景
光发射电子显微镜（Photoemission Electron Microscopy,PEEM）是一种对表面结构、电子态、化学反应等表面物理化学性质进行原位、动态研究的新技术，在化学、物理、材料等研究领域有着重要的应用。其工作原理是以紫外光或x...1科学背景
光发射电子显微镜（Photoemission Electron Microscopy,PEEM）是一种对表面结构、电子态、化学反应等表面物理化学性质进行原位、动态研究的新技术，在化学、物理、材料等研究领域有着重要的应用。其工作原理是以紫外光或x射线光来激发固体表面原子中的电子，采用电子光学系统记录光电子发射，并进行成像研究。展开更多
The interface between a two-dimensional(2D)atomic crystal and a metal surface can be regarded as a nanoreactor, in which molecule adsorption and catalytic reactions may occur. In this work, we demonstrate that oxygen ...The interface between a two-dimensional(2D)atomic crystal and a metal surface can be regarded as a nanoreactor, in which molecule adsorption and catalytic reactions may occur. In this work, we demonstrate that oxygen intercalation and desorption occur at the interface between hexagonal boron nitride(h-BN) overlayer and Pt(111) surface by using near-ambient pressure X-ray photoelectron spectroscopy(NAP-XPS), photoemission electron microscopy, and low-energy electron microscopy.Furthermore, CO oxidation under the h-BN cover was also observed by NAP-XPS. The present results indicate that the nanospace under the 2D cover can be used for surface reactions, in which novel surface chemistry may be induced by the nanoconfinement effect.展开更多
A simple hand calculation method based on group theory is proposed to predict the near field maps of finite metallic nanoparticles(MNP)of canonical geometries:prism,cube,hexagon,disk,sphere,etc.corresponding to low or...A simple hand calculation method based on group theory is proposed to predict the near field maps of finite metallic nanoparticles(MNP)of canonical geometries:prism,cube,hexagon,disk,sphere,etc.corresponding to low order localized surface plasmon resonance excitations.In this article,we report the principles of the group theory approach and demonstrate,through several examples,the general character of the group theory method which can be applied to describe the plasmonic response of particles of finite or infinite symmetry point groups.Experimental validation is achieved by collection of high-resolution subwavelength near-field maps by photoemission electron microscopy(PEEM)on a representative set of Au colloidal particles exhibiting either finite(hexagon)or infinite(disk,sphere)symmetry point groups.展开更多
文摘Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular.
文摘Hexagonal boron nitride （h-BN） is often prepared by epitaxial growth on metals, and stability of the formed BN/metal interfaces in gaseous environment is a key issue for physicochemical properties of the BN overlayers. As an illustration here, the structural change of a BN/Ru（0001） interface upon exposure to 02 has been investigated using in situ photoemission electron microscopy （PEEM） and ambient pressure X-ray photoelectron spectroscopy （AP-XPS）. We demonstrate the occurrence of oxygen intercalation of the BN overlayers in 02 atmosphere, which decouples the BN overlayer from the substrate. Comparative studies of oxygen intercalation at BN/Ru（0001） and graphene/Ru（0001） surfaces indicate that the oxygen intercalation of BN overlayers happens more easily than graphene. This finding will be of importance for future applications of BN-based devices and materials under ambient conditions.
文摘1科学背景
光发射电子显微镜（Photoemission Electron Microscopy,PEEM）是一种对表面结构、电子态、化学反应等表面物理化学性质进行原位、动态研究的新技术，在化学、物理、材料等研究领域有着重要的应用。其工作原理是以紫外光或x射线光来激发固体表面原子中的电子，采用电子光学系统记录光电子发射，并进行成像研究。
基金supported by the National Natural Science Foundation of China(21222305,21373208,and21033009)the National Basic Research Program of China(2011CB932704,2013CB933100,and 2013CB834603)+1 种基金the Key Research Program of the Chinese Academy of Science(KGZD-EWT05)The Advanced Light Source and beamlines 11.0.2 and 9.3.1 are supported by the Director,Office of Energy Research,Office of Basic Energy Sciences,and Chemical Sciences Division of the US Department of Energy under contracts No.DE-AC02-05CH11231
文摘The interface between a two-dimensional(2D)atomic crystal and a metal surface can be regarded as a nanoreactor, in which molecule adsorption and catalytic reactions may occur. In this work, we demonstrate that oxygen intercalation and desorption occur at the interface between hexagonal boron nitride(h-BN) overlayer and Pt(111) surface by using near-ambient pressure X-ray photoelectron spectroscopy(NAP-XPS), photoemission electron microscopy, and low-energy electron microscopy.Furthermore, CO oxidation under the h-BN cover was also observed by NAP-XPS. The present results indicate that the nanospace under the 2D cover can be used for surface reactions, in which novel surface chemistry may be induced by the nanoconfinement effect.
基金The CEA authors acknowledge financial support by the French National Agency(ANR)in the frame of its program in Nanosciences and Nanotechnologies(PEEM Plasmon Project ANR-08-NANO-034,ANR P2N 2013-Samiré)NanosciencesÎle-de-France(PEEM Plasmonics project)+1 种基金the“Triangle de la Physique”(PEPS Project 2012-035T)the doctoral school“Ecole Doctorale Ondes et Matière(EDOM)”.
文摘A simple hand calculation method based on group theory is proposed to predict the near field maps of finite metallic nanoparticles(MNP)of canonical geometries:prism,cube,hexagon,disk,sphere,etc.corresponding to low order localized surface plasmon resonance excitations.In this article,we report the principles of the group theory approach and demonstrate,through several examples,the general character of the group theory method which can be applied to describe the plasmonic response of particles of finite or infinite symmetry point groups.Experimental validation is achieved by collection of high-resolution subwavelength near-field maps by photoemission electron microscopy(PEEM)on a representative set of Au colloidal particles exhibiting either finite(hexagon)or infinite(disk,sphere)symmetry point groups.
