[1] Southern Univ Sci & Technol, Dept Elect & Elect Engn, Shenzhen 518055, Peoples R China
[2] Southern Univ Sci & Technol, Mat Characterizat & Preparat Ctr, Shenzhen 518055, Peoples R China
[3] Shenzhen Key Lab Third Generat Semicond, Shenzhen 518055, Peoples R China
[4] GaN Device Engn Technol Res Ctr Guangdong, Shenzhen 518055, Peoples R China