1. Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 P. R. China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. School of Materials Science and Engineering NingboTech University Ningbo 315100 P. R. China
4. Hangna Nanofabrication Equipment Co., Ltd. Hangzhou 311215 P. R. China
5. Research Center for Sensing Materials and Devices Zhejiang Lab Hangzhou 311121 P. R. China