[1] Chinese Acad Sci, Key Lab Funct Mat & Devices Special Environm, Urumqi 830011, Peoples R China
[2] Xinjiang Tech Inst Phys & Chem, Xinjiang Key Lab Elect Informat Mat & Devices, Urumqi 830011, Peoples R China
[3] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
[4] Tamkang Univ, Dept Phys, Taipei 25137, Taiwan