[1] Shandong Univ, Sch Integrated Circuit, Shandong Technol Ctr Nanodevices & Integrat, Jinan 250101, Peoples R China
[2] Mirpur Univ Sci & Technol, Dept Elect Engn, Mirpur Azad 10250, Jammu & Kashmir, Pakistan
[3] Uppsala Univ, Dept Mat Sci & Engn, S-75121 Uppsala, Sweden
[4] Shandong Univ, Shenzhen Res Inst, Shenzhen 518063, Peoples R China