[1] Anyang Normal Univ, Coll Chem & Chem Engn, Anyang 455002, Peoples R China
[2] Hunan Univ, Sch Phys & Elect, Key Lab Micro Nanooptoelect Devices, Minist Educ, Changsha 410082, Hunan, Peoples R China
[3] Univ Wollongong, Inst Superconducting & Elect Mat, Wollongong, NSW 2522, Australia