摘要
Recent advances in monochromatic aberration corrected electron microscopy make it possible to detect the lattice vibrations with both high-energy resolution and high spatial resolution. Here, we use sub-10 meV electron energy loss spectroscopy to investigate the local vibrational properties of the SiO_2/Si surface and interface. The energy of the surface mode is thickness dependent, showing a blue shift as z-thickness(parallel to the fast electron beam)of SiO_2 film increases, while the energy of the bulk mode and the interface mode keeps constant. The intensity of the surface mode is well-described by a Bessel function of the second kind. The mechanism of the observed spatially dependent vibrational behavior is discussed and compared with dielectric response theory analysis. Our nanometer scale measurements provide useful information on the bonding conditions at the surface and interface.
Recent advances in monochromatic aberration corrected electron microscopy make it possible to detect the lattice vibrations with both high-energy resolution and high spatial resolution. Here, we use sub-10 meV electron energy loss spectroscopy to investigate the local vibrational properties of the SiO_2/Si surface and interface. The energy of the surface mode is thickness dependent, showing a blue shift as z-thickness(parallel to the fast electron beam)of SiO_2 film increases, while the energy of the bulk mode and the interface mode keeps constant. The intensity of the surface mode is well-described by a Bessel function of the second kind. The mechanism of the observed spatially dependent vibrational behavior is discussed and compared with dielectric response theory analysis. Our nanometer scale measurements provide useful information on the bonding conditions at the surface and interface.
作者
Yue-Hui Li
Mei Wu
Rui-Shi Qi
Ning Li
Yuan-Wei Sun
Cheng-Long Shi
Xue-Tao Zhu
Jian-Dong Guo
Da-Peng Yu
Peng Gao
李跃辉;武媚;亓瑞时;李宁;孙元伟;施成龙;朱学涛;郭建东;俞大鹏;高鹏(International Center for Quantum Materials, Peking University;Electron Microscopy Laboratory, School of Physics, Peking University;Nion Company;Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences;Shenzhen Key Laboratory of Quantum Science and Engineering;Collaborative Innovation Centre of Quantum Matter)
基金
Supported by the National Key R&D Program of China under Grant No 2016YFA0300804
the National Natural Science Foundation of China under Grant Nos 51502007 and 51672007
the National Equipment Program of China under Grant No ZDYZ2015-1
the National Program for Thousand Young Talents of China
the ‘2011 Program’ Peking-Tsinghua-IOP Collaborative Innovation Center of Quantum Matter
