[1] Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China
[2] Beihang Univ, Sch Instrumentat Sci & Optoelect Engn, Beijing 100191, Peoples R China
[3] Chinese Acad Sci, Beijing Inst Nanoenergy & Nanosyst, Beijing 101400, Peoples R China
[4] Univ Western Ontario, Dept Mech & Mat Engn, London, ON N6A 5B9, Canada