1. School of Microelectronics, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
2. GaN Device Engineering Technology Research Center of Guangdong, SUSTech, Shenzhen 518055, China
3. Key Laboratory of the Third Generation Semiconductors, SUSTech, Shenzhen 518055, China
4. Department of Materials Engineering, The University of British Columbia (UBC), Vancouver, British Columbia V6T 1Z4, Canada
5. School of Innovation and Entrepreneurship, SUSTech, Shenzhen 518055, China