1. Dr. D. Luo, Prof. H. Yu, Prof. Z.‐H. Lu School of Microelectronics Southern University of Science and Technology Shenzhen Guangdong 518055 China
2. Dr. D. Luo, Dr. X. Li, A. Dumont, Prof. Z.‐H. Lu Department of Materials Science and Engineering University of Toronto Toronto M5G 3E4 Canada
3. Dr. X. Li, Prof. Z.‐H. Lu Department of Physics Center for Optoelectronics Engineering Research Yunnan University Kunming 650091 P. R. China