[1] Chinese Acad Sci, Key Lab Microelect Device & Integrated Technol, Beijing 100029, Peoples R China
[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China
[3] Henan Univ, Key Lab Photovolta Mat Henan Prov, Kaifeng 475004, Peoples R China
[4] East China Normal Univ, Dept Elect, Key Lab Polar Mat & Devices MOE, Shanghai 200241, Peoples R China