1. Division of Functional Materials and Nano DevicesNingbo Institute of Materials Technology and EngineeringChinese Academy of Sciences Ningbo 315201 China
2. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Sciences Beijing 100049 China
3. Nano Surfaces DivisionBruker (Beijing) Scientific Technology Co., Ltd Beijing 100192 China
4. School of Physical Science and TechnologyNingbo University Ningbo 315211 China
5. Shanghai Synchrotron Radiation FacilityShanghai Advanced Research InstituteChinese Academy of Sciences Shanghai 201210 China