[Dai, Zhiping] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.
[Wen, Feng] Xi An Jiao Tong Univ, Sch Sci, Key Lab Phys Elect & Devices, Minist Educ, Xian 710049, Shaanxi, Peoples R China.
[Yang, Zhenjun; Jia, Shuai] Hebei Normal Univ, Coll Phys, Shijiazhuang 050024, Hebei, Peoples R China.
[Yang, Zhenjun; Jia, Shuai] Hebei Normal Univ, Hebei Adv Thin Film Lab, Shijiazhuang 050024, Hebei, Peoples R China.