[Yang, Jianhua;Liu, Rujun;Huang, Sheng;Huang, Yuan;Yu, Ying] Cent China Normal Univ, Coll Phys Sci & Technol, Inst Nanosci & Nanotechnol, Wuhan 430079, Peoples R China.^[Shao, Yu] Univ Sci & Technol China, Coll Mat Sci & Engn, Anhua 230026, Peoples R China.