[Ling, Xiaohui] Hengyang Normal Univ, Coll Phys & Elect Engn, Hunan Prov Key Lab Intelligent Informat Proc & Ap, Hengyang 421002, Peoples R China.
[Qiu, Cheng-Wei; Ling, Xiaohui] Natl Univ Singapore, Dept Elect & Comp Engn, 4 Engn Dr 3, Singapore 117576, Singapore.
[Wen, Shuangchun; Luo, Hailu; Ling, Xiaohui; Liu, Yachao] Hunan Univ, Sch Phys & Elect, Minist Educ, Lab Micro Nanooptoelect Devices, Changsha 410082, Hunan, Peoples R China.
[Zhou, Xinxing] Hunan Normal Univ, Coll Phys & Informat Sci, Synerget Innovat Ctr Quantum Effects & Applicat, Changsha 410081, Hunan, Peoples R China.
[Huang, Kun] Agcy Sci Technol & Res, Inst Mat Res & Engn, 2 Fusionopolis Way,Innovis 08-03, Singapore 138634, Singapore.