[1] Univ Elect Sci & Technol China, Sch Integrated Circuit Sci & Engn, Chengdu 610054, Peoples R China
[2] Univ Elect Sci & Technol China, State Key Lab Elect Thin Films & Integrated Device, Chengdu 610054, Peoples R China
[3] Tibet Univ, Coll Sci, Lhasa 850000, Peoples R China
[4] Tibet Univ, Inst Oxygen Supply, Everest Res Inst, Ctr Tibetan Studies, Lhasa 850000, Peoples R China