[1] Zhengzhou Univ, Sch Phys & Microelect, Key Lab Mat Phys, Minist Educ, Zhengzhou 450052, Peoples R China
[2] Dalian Minzu Univ, Sch Phys & Mat Engn, Key Lab New Energy & Rare Earth Resource Utilizat, Dalian 116600, Peoples R China
[3] Jilin Univ, Coll Elect Sci & Engn, State Key Lab Integrated Optoelect, Changchun 130012, Peoples R China
[4] Fudan Univ, Dept Mat Sci, Shanghai 200433, Peoples R China