[1] Shanghai Univ, Dept Phys, Shanghai 200444, Peoples R China
[2] Chinese Acad Sci, Shanghai Adv Res Inst, Thin Film Optoelect Technol Ctr, Shanghai 201210, Peoples R China
[3] Shanghai Univ, Dept Mat Sci & Engn, Shanghai 200444, Peoples R China
[4] Shanghai Tech Univ, Sch Phys Sci & Technol, Shanghai 201210, Peoples R China
[5] 99 Haike Rd,Zhangjiang Hitech Pk, Shanghai 201210, Peoples R China