1. School of Materials Sciences and Engineering; College of Engineering Peking University Beijing 100871 China
2. CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center of Excellence for Nanoscience National Center for Nanoscience and Technology Beijing 100190 China
3. Beijing Key Laboratory for Optical Materials and Photonic Devices Department of Chemistry Capital Normal University Beijing 100048 China
4. State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Department of Physics Peking University Beijing 100871 China
5. Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials Engineering University of Macau Avenida da Universidade Taipa Macao SAR 999078 China