[1] South China Normal Univ, Coll Biophoton, Guangzhou 510631, Guangdong, Peoples R China
[2] Guangdong Acad Sci, Inst Semicond, Guangzhou 510650, Peoples R China
[3] Guilin Univ Elect Technol, Sch Mat Sci & Engn, Guangxi Key Lab Informat Mat, Guilin 541004, Peoples R China