[1] Tsinghua Univ, Natl Ctr Electron Microscopy Beijing, Key Lab Adv Mat MOE, State Key Lab New Ceram & Fine Proc,Sch Mat Sci &, Beijing 100084, Peoples R China
[2] Tsinghua Univ, Cent Nano & Micro Mech, Beijing 100084, Peoples R China
[3] Tsinghua Univ, Key Lab Adv Mat MOE, Sch Mat Sci & Engn, Beijing 100084, Peoples R China
[4] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China
[5] City Univ Hong Kong, Dept Mat Sci & Engn, Kowloon, Tat Chee Ave, Hong Kong, Peoples R China
[6] City Univ Hong Kong, Nanomfg Lab NML, Shenzhen Res Inst, Shenzhen 518057, Peoples R China