1. State
Key Laboratory on Integrated Optoelectronics, College of Electronic
Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, China
2. State
Key Laboratory of Luminescence and Applications, Changchun Institute
of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China
3. Department
of Mechanical and Materials Engineering and Nebraska Center for Materials
and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0656, United States