1. Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University; No.28, Xianning West Road Xi'an 710049 China
2. Department of Materials Science and Engineering, University of Washington; Seattle WA 98195 USA
3. Department of Materials Science and Metallurgy, University of Cambridge; Cambridge CB3 0FS UK
4. School of Electronic Enginnering, Xi'an University of Post & Telecommunication; Xi'an 710121 China
5. Department of Materials Science & Engineering, City University of Hong Kong; Kowloon 999077 Hong Kong
6. Collaborative Innovation Center of Extreme Optics,; Shanxi University; Taiyuan 030006 China