[1] Chinese Univ Hong Kong, Dept Elect Engn, Mat Sci & Technol Res Ctr, Shatin, Hong Kong, Peoples R China
[2] Chinese Univ Hong Kong, Dept Elect Engn, Mat Sci & Technol Res Ctr, Shatin, Hong Kong, Peoples R China
[3] Hong Kong Univ Sci & Technol, Inst Nano Sci & Technol, Kowloon, Hong Kong, Peoples R China
[4] Hong Kong Univ Sci & Technol, Dept Phys, Kowloon, Hong Kong, Peoples R China
[5] Wuhan Univ Technol, State Key Lab Adv Technol Mat Synth & Proc, Wuhan 430070, Peoples R China
[6] Chinese Univ Hong Kong, Dept Phys, Shatin, Hong Kong, Peoples R China