[1] Univ Elect Sci & Technol China, Inst Fundamental & Frontier Sci, Chengdu 611731, Peoples R China
[2] Jiangsu Univ Technol, Sch Mat Engn, Changzhou 213001, Peoples R China
[3] Univ Glasgow, James Watt Sch Engn, Univ Ave, Glasgow City G12 8 QQ, Scotland
[4] Natl Univ Sci & Technol, Sch Nat Sci, Dept Chem, Islamabad 44000, Pakistan
[5] Allama Iqbal Open Univ, Dept Phys, Islamabad 44000, Pakistan
[6] Univ Kebangsaan Malaysia, Inst Microengn & Nanoelect, Bangi 43600, Malaysia
[7] Ohio Univ, Dept Phys & Astron, Athens, OH 45701 USA
[8] Shimmer Ctr, Tianfu Jiangxi Lab, Chengdu 641419, Peoples R China