[1] Chinese Acad Sci, Inst Plasma Phys, HFIPS, Hefei 230031, Anhui, Peoples R China
[2] CAS Key Lab Photovolta & Energy Conservat Mat, Hefei 230031, Anhui, Peoples R China
[3] Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA
[4] Inst Energy, Hefei Comprehens Natl Sci Ctr, Hefei 230026, Anhui, Peoples R China
[5] Dalian Univ Technol, Sch Phys & Optoelect Technol, Dalian 116024, Liaoning, Peoples R China