[1] Chinese Acad Sci, Beijing Inst Nanoenergy & Nanosyst, Beijing 101400, Peoples R China
[2] Wuhan Univ Sci & Technol, Minist Educ, Key Lab Met Equipment & Control Technol, Wuhan 430081, Hubei, Peoples R China
[3] Univ Chinese Acad Sci, Sch Nanosci & Technol, Beijing 100049, Peoples R China
[4] Univ Chinese Acad Sci, Coll Mat Sci & Optoelect Technol, Beijing 101408, Peoples R China
[5] Ningbo Univ, Fac Elect Engn & Comp Sci, Ningbo 315211, Peoples R China
[6] Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA