[1] Chongqing Univ, Inst Struct & Funct, Chongqing 401331, Peoples R China
[2] CAEP, Microsyst & Terahertz Res Ctr, Microsyst Technol Lab, Chengdu 610200, Sichuan, Peoples R China
[3] King Saud Univ, Coll Sci, Dept Phys & Astron, Riyadh 11451, Saudi Arabia
[4] Chongqing Jiaotong Univ, Coll Mat Sci & Engn, Chongqing 402247, Peoples R China