Zhang Hui, Li Xiaobao, Wang Wei, Mao Baohua, Han Yong, Yu Yi, Liu Zhi
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Rev Sci Instrum. 2020 Dec 1;91(12):123108. doi: 10.1063/5.0020469.
During the past few decades, resonant Auger spectroscopy (RAS) has presented some advantages in elucidating the electronic structure of free molecules, liquids, and solids. To further extend the application of RAS in complex in situ environments, the ambient pressure system should be developed to characterize the gas-solid and liquid-solid interfaces. In this paper, we describe the design and performance of an ambient pressure mapping of resonant Auger spectroscopy (mRAS) system newly developed at BL02B01 at the Shanghai Synchrotron Radiation Facility. This system is unique in that the ambient pressure soft x-ray absorption spectroscopy (sXAS) can be measured in Auger electron yield with kinetic energy (KE) resolved. We can obtain a mapping of the resonant Auger spectroscopy (mRAS) in the near ambient pressure environment. This approach provides an additional dimension of information along the KE of Auger electrons to reveal details of the valence and unoccupied states at the vicinity of the absorption edge. Complementary to the photoemission spectroscopy that probes the core levels, in situ two-dimension mRAS characterization is useful in studying the electronic structure of complex interfaces of gas-solid and liquid-solid under realistic operating conditions. We herein present the in situ oxidation of Cu(111) in the ambient oxygen environment as demonstration of the mRAS capability. Specifically, resolving the Auger features gives valuable clues to the molecular level understanding of chemical bonding and the evolution of orbital hybridization. In addition, the mRAS results of spatial resolution and mbar range gas pressure are shown and discussed.
在过去几十年中，共振俄歇光谱（RAS）在阐明自由分子、液体和固体的电子结构方面展现出了一些优势。为了进一步扩展RAS在复杂原位环境中的应用，应开发常压系统来表征气固和液固界面。在本文中，我们描述了上海同步辐射装置BL02B01新开发的共振俄歇光谱常压成像（mRAS）系统的设计与性能。该系统的独特之处在于，可以在动能（KE）分辨的俄歇电子产额中测量常压软X射线吸收光谱（sXAS）。我们能够在近常压环境中获得共振俄歇光谱成像（mRAS）。这种方法沿着俄歇电子的动能提供了额外的信息维度，以揭示吸收边附近价态和未占据态的细节。与探测芯能级的光电子能谱互补，原位二维mRAS表征对于研究实际操作条件下气固和液固复杂界面的电子结构很有用。我们在此展示了在常压氧气环境中Cu(111)的原位氧化，以证明mRAS的能力。具体而言，解析俄歇特征为化学键合的分子水平理解和轨道杂化的演变提供了有价值的线索。此外，还展示并讨论了空间分辨率和毫巴级气压范围的mRAS结果。
