[1] Hunan Univ, Sch Phys & Elect, Changsha 430001, Peoples R China
[2] Tsinghua Univ, Sch Integrated Circuits, Beijing 100084, Peoples R China
[3] Hunan Univ, Coll Elect & Informat Engn, Changsha 430001, Peoples R China
[4] Hunan Univ, Coll Semicond, Coll Integrated Circuits, Changsha 430001, Peoples R China
[5] Hunan Univ, Shenzhen Res Inst, Shenzhen 518055, Peoples R China