1State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
2Department of Electrical Engineering and Photonics Research Institute, The Hong Kong Polytechnic University, Hong Kong 518060, China
3State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
4Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA