[1] Natl Univ Singapore, Dept Chem, 3 Sci Dr 3, Singapore 117543, Singapore
[2] Univ Sci & Technol China, Hefei Natl Lab Phys Sci Microscale, CAS Ctr Excellence, Hefei 230026, Peoples R China
[3] Univ Sci & Technol China, Synerget Innovat Ctr Quantum Informat & Quantum P, Hefei 230026, Peoples R China
[4] Natl Univ Singapore, Dept Phys, 2 Sci Dr 3, Singapore 117542, Singapore
[5] Shenzhen Univ, SZU NUS Collaborat Innovat Ctr Optoelect Sci & Te, Shenzhen 518060, Peoples R China
[6] Nanchang Univ, Inst Adv Study, 999 Xue Fu Da Dao, Nanchang 330031, Jiangxi, Peoples R China
[7] Nanchang Univ, Dept Phys, 999 Xue Fu Da Dao, Nanchang 330031, Jiangxi, Peoples R China
[8] Nanjing Tech Univ, Nanjing Tech, Jiangsu Natl Synerget Innovat Ctr Adv Mat SICAM, KLOFE, 30 South Puzhu Rd, Nanjing 211816, Jiangsu, Peoples R China
[9] Nanjing Tech Univ, Nanjing Tech, Jiangsu Natl Synerget Innovat Ctr Adv Mat SICAM, IAM, 30 South Puzhu Rd, Nanjing 211816, Jiangsu, Peoples R China
[10] Nanjing Univ Posts & Telecommun NJUPT, IAM, 9 Wenyuan Rd, Nanjing 210023, Jiangsu, Peoples R China
[11] Natl Univ Singapore Suzhou, Res Inst, 377 Lin Quan St,Suzhou Ind Pk, Suzhou 215123, Peoples R China
[12] Natl Univ Singapore, Ctr Adv Mat 2D, 3 Sci Dr 3, Singapore 117546, Singapore
[13] Natl Univ Singapore, Graphene Res Ctr, 3 Sci Dr 3, Singapore 117546, Singapore